Log Tags Documentation for SnapRAID.

1 Description

This document describes the structured log tags output by SnapRAID, which are designed to be used by tools monitoring the SnapRAID processing state. The tags provide information in an easy-to-parse format, ideal for automation and integration.

To capture these structured log tags, you must use the `--log` option with SnapRAID.

You can direct the output to a specific file, or force the output to the standard output or standard error using the special arguments `>&1` or `>&2`. Note that these arguments often need to be quoted on the command line to prevent the shell from interpreting them.

Example: 

snapraid status --log ">&2"

The output tags strictly adhere to the following format: 

NAME:VALUE:VALUE:VALUE...<EOL>
NAME
This is the primary tag identifier, always a lowercase string without spaces (e.g., `summary`, `block`, `info_time`).
VALUE
Following the `NAME`, these can be additional sub-identifiers, descriptive names (like a disk name), or numeric/string data values. They are separated by a colon `:`.
<EOL>
Each tag is terminated by an end-of-line character.

This document provides a summary of the tags generated by SnapRAID. For the most detailed and up-to-date information regarding the meaning and context of the values, it is recommended to check the source code's `log_tag()` statements.

When a path is output, it is always escaped using a backslash (\) as the escape character.

The following characters are escaped into sequences:

The colon is escaped to \d.
The newline is escaped to \n.
The carriage return is escaped to \r.
The backslash is escaped to \\.

Some tags are output only when the `--gui` option is used. They provide extra verbose state and runtime progress only useful for a GUI interface.

2 Configuration Tags

These tags report the memory usage and global configuration after scanning the disk and reading the list of files.

conf:file:<path>
Configuration file loaded (escaped).
conf:missing:
Operating without a configuration file.
blocksize:<bytes>
The configured block size in bytes (uint).
data:<disk_name>:<dir>
The data disks as defined in the configuration file.
<disk_name> The assigned name of the disk.
<dir> The directory entry point of the disk.
mode:<raidname>
The RAID mode used. One of `par1`, `par2`, `par3`, `par4`, `par5`, `par6` or `parz`. The number indicates the maximum number of simultaneous disk failures the array can withstand.
<parity_level>:<split_index>:<path>
The parity files as defined in the configuration file.
<parity_level> One of `parity`, `2-parity`, ..., `6-parity`. This corresponds to the level of redundancy.
<split_index> The split index (uint). If no multiple split parity is configured, there is only the index 0. A split parity configuration distributes parity blocks across multiple files.
<path> The path (escaped).
pool:<dir>
The configured dir to the pool mount point (escaped). This is the optional mount point for the 'pool' feature.
share:<dir>
The configured dir to the pool mount point (escaped). This is the optional mount point for the 'share' feature.
autosave:<bytes>
If the autosave feature is enabled, and after how many bytes (uint64). This specifies the interval for content file saving.
filter:<pattern>
All the active filters with their patterns. These patterns exclude specific files or directories from the SnapRAID array.
filter:nohidden:
If the no-hidden filter is enabled, meaning hidden files/directories (starting with '.') are excluded from the array.
content:<path>
The absolute path to a content file being used (escaped). Content files store the metadata (like file hashes and timestamps) for the array.
content:<parity_level>:<split_index>:<path>:<uuid>:<size>
The parity files as stored in the content file.
<parity_level> One of `parity`, `2-parity`, ..., `6-parity`.
<split_index> The split index (uint). If no multiple split parity is configured, there is only the index 0.
<path> The path (escaped).
<uuid> The UUID of the partition containing the path.
<size> The size of the parity file. Size is -1 if not yet fixed, meaning it can grow. This happens for the latest split.

3 Diagnostics Tags

version:<version>
The version of SnapRAID run.
unixtime:<time>
The current time in the unix format (uint64), representing seconds since the epoch.
time:<YYYY-MM-DD HH:MM:SS>
The current time in human format.
command:<command>
The command run. One of `sync`, `scrub`, `check`, `fix`, `status`, ...
argv:<number>:<argument>
All the arguments of the executable command. The 0 one is the executable run.
memory:used:<bytes>
The total memory currently used by the application in bytes (uint64).
memory:block:<bytes>
Size of the internal `snapraid_block` structure in bytes (uint64).
memory:extent:<bytes>
Size of the internal `snapraid_extent` structure in bytes (uint64).
memory:file:<bytes>
Size of the internal `snapraid_file` structure in bytes (uint64).
memory:link:<bytes>
Size of the internal `snapraid_link` structure in bytes (uint64).
memory:dir:<bytes>
Size of the internal `snapraid_dir` structure in bytes (uint64).

4 Scan Tags

These tags report detected differences between the filesystem and the content file. They are output for every discovered change, and `scan:equal` is only output when the `--gui` option is used.

scan:equal:<disk_name>:<path>
A file, link, or directory is equal (unchanged) (GUI only). No action is required for this item.
<disk_name> Name of the data disk.
<path> Path to the file/link/dir relative to the disk mount (escaped).
scan:add:<disk_name>:<path>
A new file, link, or directory was found that is not in the content file. This item will be added to the array in a `sync`.
scan:remove:<disk_name>:<path>
A file, link, or directory has been removed from the filesystem since the last sync. This item will be removed from the content file in a `sync`.
scan:update:<disk_name>:<path>
A file or link has been updated (size, timestamp, or link target changed). This item will have its content data blocks re-hashed in a `sync`.
scan:move:<disk_name>:<old_path>:<new_path>
A file was moved on the same disk. This is an efficient operation that only updates the path metadata without re-hashing blocks.
<old_path> The old path to the file (escaped).
<new_path> The new path to the file (escaped).
scan:copy:<disk_name>:<path>:<source_disk>:<source_path>
A new file was found to be a copy of a file from another disk. This is detected by matching file size and timestamp, and is an efficient operation that avoids re-hashing all blocks.
<source_disk> The original file's disk.
<source_path> The original file's location (escaped).
scan:restore:<disk_name>:<path>
A file's inode has changed but not its date-time and size, which suggests the file may be restored from backup. The file won't be re-hashed in `sync` as its precomputed hash is assumed to be correct.

These tags provide a final count of all detected changes.

summary:equal:<count>
Total number of equal (unchanged) files/links/firs found (uint).
summary:added:<count>
Total number of new files/links/dirs found (uint).
summary:removed:<count>
Total number of removed files/links/dirs found (uint).
summary:updated:<count>
Total number of updated files/links found (uint).
summary:moved:<count>
Total number of moved files found (uint).
summary:copied:<count>
Total number of copied files found (uint).
summary:restored:<count>
Total number of restored files found (uint).
summary:exit:equal
A zero-argument tag indicating that no differences were found. The array is already synchronized.
summary:exit:diff
A zero-argument tag indicating that differences were found. The array needs a `sync` operation.

5 General Progress and Execution Tags

These tags are used to report the runtime processing of the commands. Only produced when `--gui` option is used.

run:begin:<blockstart>:<blockend>:<countmax>
A tag indicating the start of the command execution.
<blockstart> Starting block index (uint).
<blockend> Ending block index + 1 (uint).
<countmax> Number of blocks to process. It may be less than <blockend> - <blockstart> + 1 if some blocks are going to be skipped (uint).
run:end
A zero-argument tag indicating the end of the command execution.
run:pos:<blockpos>:<countpos>:<countsize>:<perc>:<eta>:<size_speed>:<cpu>:<elapsed>
Detailed progress information during command execution.
<blockpos> Current block index position (uint).
<countpos> Current item count position (uint).
<countsize> Current size processed (uint64).
<perc> Percentage complete (uint).
<eta> Estimated time of arrival in minutes (uint).
<size_speed> Data processing speed in MiB/s (uint).
<cpu> CPU usage percentage (uint).
<elapsed> Elapsed time in seconds (uint64).
sigint:<blockpos>:<msg>
A user interruption (e.g., Ctrl+C) was signaled. The process is gracefully aborting.
<blockpos> Current block index position (uint).
<msg> Text message exactly as it's printed on screen.
msg:<level>:<msg>
Messages printed to the screen.
<level> One of `fatal`, `error`, `expected`, `status`, `progress` or `verbose`.
fatal A fatal error occurred. Program will abort after this message.
error A generic error condition that doesn't prevent the program to continue.
expected An expected error condition. At present it happens only when using the `-m` option with files expected missing.
status A status message, usually providing context or a summary.
progress A progress message, often part of an ongoing operation.
verbose A verbose informative message, only shown in verbose mode.
<msg> Text message exactly as it's printed on screen.

6 Thermal Tags

The following tags are produced by the thermal monitoring functions when SnapRAID is processing, typically during operations that involve disk access.

thermal:ambient:device:<hwmon_dir>:<name>:<temp_file>:<label>:<temp>
Logs a temperature reading found in the system using the Linux /sys/class/hwmon interface. Only present in Linux.
<hwmon_dir> The hwmon directory name (e.g., hwmon0).
<name> The name of the hwmon device (e.g., k10temp).
<temp_file> The temperature file name (e.g., temp1_input).
<label> The label associated with the temperature sensor (e.g., Tdie).
<temp> The temperature reading in degrees Celsius.
thermal:ambient:candidate:<temp>
Reports a temperature reading that is a candidate for the ambient temperature, used in the heating model calculation.
<temp> The candidate temperature in degrees Celsius.
thermal:system:candidate:<temp>
Logs a temperature reading from a connected disk that is being considered as a candidate for determining the ambient system temperature.
<temp> The current temperature read from the disk (uint, degrees Celsius).
thermal:system:final:<temp>
Logs the final ambient system temperature calculated. This value is the lowest valid temperature observed among all candidates, representing the room temperature.
<temp> The calculated ambient temperature in degrees Celsius.
thermal:current:<disk_name>:<device>:<temp>
Logs the most recent temperature reading for a specific disk device.
<disk_name> The configured name of the disk.
<device> The unique device ID (uint64).
<temp> The current temperature read from the disk in degrees Celsius.
thermal:highest:<temp>
Logs the highest temperature observed among all monitored disks in the current measurement cycle. This is used for thermal throttling.
<temp> The highest temperature observed in degrees Celsius.
thermal:heat:<disk_name>:<device>:<count>:<data_points>
Logs the entire history of temperature data points collected so far for a specific disk, used for fitting the heating model. Only monotone increasing temperatures are included in the history.
<disk_name> The configured name of the disk.
<device> The unique device ID (uint64).
<count> The total number of collected data points (uint).
<data_points> A comma-separated list of temperature/time pairs. Each pair is formatted as <temp>/<time_offset>.
<temp> Temperature reading in degrees Celsius.
<time_offset> Time offset from the start of the thermal monitoring (uint, seconds).
thermal:params:<disk_name>:<device>:<k_heat>:<t_ambient>:<t_steady>:<rmse>:<r_squared>:<max_error>
Logs the estimated parameters for the exponential heating model (fit using least squares) and associated quality metrics for a specific disk. The model is: T(t) = T_steady - (T_steady - T_0) e^(-kt), where T_0 is the initial temperature.
<disk_name> The configured name of the disk.
<device> The unique device ID (uint64).
<k_heat> The heating rate constant, k (double).
<t_ambient> The ambient temperature, T_ambient (double).
<t_steady> The estimated steady-state temperature, T_steady (double), which is the maximum expected temperature of the disk.
<rmse> Root Mean Square Error of the fit (double).
<r_squared> Coefficient of determination (R^2) of the fit (double).
<max_error> Maximum absolute error of the fit (double).
thermal:spindown
Indicates that the thermal alarm limit has been reached, and the process is initiating a disk spindown to begin the cooldown procedure, preventing overheating.
thermal:cooldown:<sleep_time>
Indicates the duration of the cooldown waiting period after spindown.
<sleep_time> The total time the system will wait for cooldown (uint, seconds).
thermal:spinup
Indicates that the cooldown period is complete, and the disks are being spun back up to resume the operation.

7 Command Status Tags

This section describes the tags output with the `status` command.

Summary Tags

These tags provide general information about the array configuration and overall state.

summary:block_size:<uint>
The size of a block in bytes. This is the unit of parity protection.
summary:parity_block_count:<uint>
The total number of blocks allocated for all parity levels combined.
summary:parity_block_total:<name>:<uint>
Total blocks available for a specific parity level (e.g., `parity`, `2-parity`).
summary:parity_block_free:<name>:<uint>
Free blocks available for a specific parity level.
summary:parity_block_free_min:<uint>
The minimum number of free blocks across all parity levels. This determines the maximum size of data that can be added.
summary:file_count:<uint>
Total number of files in the array.
summary:file_block_count:<uint64>
Total number of data blocks used by files.
summary:fragmented_file_count:<uint>
Total number of fragmented files, meaning files whose blocks are not contiguous.
summary:excess_fragment_count:<uint>
Total number of excess fragments (one less than the total fragments). This is a measure of data fragmentation overhead.
summary:zerosubsecond_file_count:<uint>
Total number of files with a zero sub-second timestamp. This can occur on certain filesystems and may affect change detection.
summary:file_size:<uint64>
Total size of all files in bytes.
summary:parity_size:<uint64>
Total size of allocated parity blocks in bytes.
summary:parity_size_max:<uint64>
Maximum possible parity size (allocated + min free) in bytes. This is the effective maximum protection size.
summary:hash:<name>
The current hash algorithm in use (e.g., `sha256`).
summary:prev_hash:<name>
The previous hash algorithm used, if a rehash is in progress.
summary:best_hash:<name>
The best hash algorithm for optimal performance based on system capabilities.
summary:total_wasted:<uint64>
Total wasted space (space on data disks exceeding parity capacity) in bytes.
summary:total_used:<uint64>
Total used space by data files in bytes.
summary:total_free:<uint64>
Total free space (usable by data) in bytes, limited by parity capacity.
summary:total_use_percent:<uint>
Overall array use percentage.
summary:has_unsynced:<uint>
Count of blocks that are unsynced (need a sync), meaning their parity data is out of date.
summary:has_unscrubbed:<uint>
Count of blocks that are unscrubbed (just synced), meaning they have never been verified since the last sync.
summary:has_rehash:<uint>
Count of blocks needing a rehash, usually due to a content file update or hash algorithm change.
summary:has_bad:<count>:<first>:<last>
Count of bad blocks, along with the first and last bad block index. Bad blocks indicate data or parity corruption.
summary:scrub_oldest_days:<uint>
Days ago the oldest block was last scrubbed.
summary:scrub_median_days:<uint>
Days ago the median block was last scrubbed.
summary:scrub_newest_days:<uint>
Days ago the newest block was last scrubbed.

Per-Disk Tags

These tags provide statistics for individual data disks. <name> is the disk name.

summary:disk_file_count:<name>:<uint>
Number of files on the disk.
summary:disk_block_count:<name>:<uint>
Number of blocks used by files on the disk.
summary:disk_fragmented_file_count:<name>:<uint>
Number of fragmented files on the disk.
summary:disk_excess_fragment_count:<name>:<uint>
Number of excess fragments on the disk.
summary:disk_zerosubsecond_file_count:<name>:<uint>
Number of files with zero sub-second timestamp on the disk.
summary:disk_file_size:<name>:<uint64>
Total size of files on the disk in bytes.
summary:disk_block_allocated:<name>:<uint>
Highest block index used on the disk + 1.
summary:disk_block_total:<name>:<uint>
Total blocks on the disk (physical size).
summary:disk_block_free:<name>:<uint>
Free blocks on the disk.
summary:disk_block_max_by_space:<name>:<uint>
Total blocks by disk space (used + free blocks), representing the physical limit of the disk.
summary:disk_block_max_by_parity:<name>:<uint>
Total blocks limited by parity space (parity size + min parity free blocks). This is the logical limit imposed by the parity files.
summary:disk_block_max:<name>:<uint>
Maximum usable blocks (minimum of `..._by_space` and `..._by_parity`).
summary:disk_space_wasted:<name>:<int64>
Wasted space on the disk in bytes (positive if disk is larger than usable parity space).
summary:disk_used:<name>:<uint64>
Used space on the disk in bytes.
summary:disk_free:<name>:<uint64>
Free usable space on the disk in bytes, limited by `disk_block_max`.
summary:disk_use_percent:<name>:<uint>
Disk use percentage relative to `disk_block_max`.

File Timestamp Tags

These tags list files with zero sub-second timestamps.

zerosubsecond:<disk_name>:<file_path>
Lists files that have a zero sub-second timestamp. Up to 50 are logged per disk.

Block Information Tags

These tags are generated when the GUI option is enabled (`state->opt.gui`).

block_count:<uint>
The total number of blocks in the array.
block:<index>:<time>:<used>:<unsynced>:<bad>:<rehash>
Status of a specific block.
<index> Block index.
<time> Last scrub time (Unix timestamp). A value of 0 means the block has never been scrubbed.
<used> `used` if the block contains data, otherwise empty.
<unsynced> `unsynced` if the block needs a sync, otherwise empty.
<bad> `bad` if the block has errors, otherwise empty.
<rehash> `rehash` if the block needs a rehash, otherwise empty.
block_noinfo:<index>:<used>:<unsynced>
Status of an unused block (no info recorded) in the content file.
<index> Block index.
<used> `used` if the block contains data, otherwise empty.
<unsynced> `unsynced` if the block needs a sync, otherwise empty.

Scrub History Tags

These tags provide details on the scrub/sync time distribution.

info_count:<uint>
Total number of info records about past scrub and sync operations stored in the content file.
info_time:<time>:<count>:<status>
All the info records.
<time> Unix timestamp of the scrub/sync.
<count> Number of blocks processed at this timestamp.
<status> "scrubbed" (for blocks verified to be correct) or "new" (for synced blocks that haven't been scrubbed yet).
scrub_graph_range:<max_columns>:<max_height>
Dimensions of the scrub history graph obtained from the `info_time` records. This provides the boundary for the precomputed graph data available in the `scrub_graph_bar` tags.
<max_columns> The number of columns in the graph (constant GRAPH_COLUMN).
<max_height> The maximum height (peak count) of blocks found in any column (the highest sum of scrubbed and new blocks).
scrub_graph_bar:<index>:<days_ago>:<scrubbed>:<new>
Data for a column of the scrub history graph. Each column represents a time period.
<index> Column index. From 0 to max_columns - 1.
<days_ago> Days ago for this column's time range.
<scrubbed> Count of scrubbed blocks in that day range.
<new> Count of newly synced (unscrubbed) blocks in that day range.

8 Command Sync/Scrub Tags

Tags specific for the `sync` and `scrub` commands. Also the error tags are possible.

Summary Tags

These tags provide summary statistics at the end of the command.

hash_summary:error_file:<count>
Logs the total count of file-related errors that caused a block to be skipped during the hashing phase. These are often due to file changes (missing, size/time change) during the sync operation. This happens only in `sync`.
<count> Total number of file errors (uint).
summary:error_file:<count>
Logs the total count of file-related errors encountered during the process (e.g., missing files, file attribute changes).
<count> The total number of file errors encountered (uint).
summary:error_io:<count>
Logs the total count of input/output errors encountered on data or parity disks.
<count> The total number of I/O errors encountered (uint).
summary:error_data:<count>
Logs the total count of "silent data errors" (data blocks not matching their expected hash) encountered during the sync process.
<count> The total number of silent data errors encountered (uint).
summary:exit:<status>
Logs the overall exit status of the command. The `status` is one of the following:
ok No errors were found.
error If any errors were found (file, I/O, or data errors).

9 Command Check/Fix Tags

Tags specific for the `check` and `fix` commands. Also the error tags are possible.

Fixed/Recovered Tags

These tags log successful repairs during fix operations.

fixed:<block_pos>:<disk_name>:<file_path>:<msg>
Indicates that a file was successfully fixed using parity data.
<block_pos> The block position being processed (uint).
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed size`, `Fixed data error at position...`).
parity_fixed:<block_pos>:<parity>:<msg>
Indicates that corrupted parity data was successfully recomputed and written.
<block_pos> The block position being processed (uint).
<parity> The name of the parity level (e.g., "parity", "2-parity").
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed data error`).
empty_fixed:<disk_name>:<file_path>:<msg>
Logs successful recreation of a missing or corrupted empty file.
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed empty file`).
hardlink_fixed:<disk_name>:<link_path>:<msg>
Logs successful recreation of a hard link during fix operation.
<disk_name> The name of the disk.
<link_path> The hard link path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed hardlink error`).
symlink_fixed:<disk_name>:<link_path>:<msg>
Logs successful recreation of a symbolic link during fix operation.
<disk_name> The name of the disk.
<link_path> The symlink path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed symlink error`).
dir_fixed:<disk_name>:<dir_path>:<msg>
Logs successful recreation of a missing directory during fix operation.
<disk_name> The name of the disk.
<dir_path> The directory path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the fix (e.g., `Fixed dir error`).

Unrecoverable Error Tags

These tags log errors that could not be recovered.

unrecoverable:<block_pos>:<disk_name>:<file_path>:<msg>
Indicates that a block error could not be fixed due to insufficient parity or other recovery limitations.
<block_pos> The block position being processed (uint).
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the problem (e.g., `Unrecoverable error at position <file_pos>`, `Unrecoverable unsynced error at position <file_pos>`).
collision:<disk_name>:<file_path>:<collision_path>:<msg>
Logs that the modification time was not set on a recovered file to avoid inode collision with another file.
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
<collision_path> The path of the colliding file (escaped).
<msg> A descriptive message indicating the nature of the problem (e.g., `Not setting modification time to avoid inode collision`).

File Status Tags

These tags log the final status of files after processing.

status:unrecoverable:<disk_name>:<file_path>
Indicates that a file has unrecoverable errors and was renamed to `.unrecoverable` (in fix mode) or cannot be recovered (in check mode).
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
status:recovered:<disk_name>:<file_path>
Logs that a file was successfully recovered during fix operation.
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
status:damaged:<disk_name>:<file_path>
Indicates that a file is damaged (in audit-only mode, e.g., using `check`).
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
status:recoverable:<disk_name>:<file_path>
Logs that a file has errors but could be recovered in fix mode.
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).
status:correct:<disk_name>:<file_path>
Indicates that a file passed all checks successfully (verbose mode only).
<disk_name> The name of the disk.
<file_path> The file path relative to disk root (escaped).

Summary Tags

These tags provide summary statistics at the end of the command.

summary:error:<error_count>
Logs the total number of errors encountered.
<error_count> Total number of errors (uint).
summary:error_recovered:<recovered_count>
Logs the total number of errors successfully recovered (fix mode only).
<recovered_count> Number of recovered errors (uint).
summary:error_unrecoverable:<unrecoverable_count>
Logs the total number of unrecoverable errors (not in audit-only mode).
<unrecoverable_count> Number of unrecoverable errors (uint).
summary:exit:<status>
Logs the overall exit status of the command. The `status` is one of the following:
`ok` Indicates that the operation completed with no errors.
`recovered` Indicates that the operation completed with all errors successfully recovered (fix mode only).
`recoverable` Indicates that errors were found but are all recoverable (check mode only).
`unrecoverable` Indicates that unrecoverable errors were found.
`error` Indicates that errors were found (audit-only mode).

10 Command List Tags

This section describes the tags output with the `list` command.

List Tags

These tags log details about individual files and links processed during the listing operation.

file:<disk_name>:<subpath>:<size>:<mtime_sec>:<mtime_nsec>:<inode>
Logs details for a regular file found on a disk.
<disk_name> The configured name of the disk.
<subpath> The path of the file relative to the disk's root (escaped).
<size> The size of the file in bytes (uint64).
<mtime_sec> The file's modification time in seconds since the Epoch (int64).
<mtime_nsec> The file's modification time nanosecond component (uint).
<inode> The file's inode number (int64).
link_<type>:<disk_name>:<subpath>:<linkto>
Logs details for a link found on a disk. The `<type>` component varies based on the kind of link.
<type> The type of link, one of: `hardlink`, `symlink`, `symdir` (symlink to a directory), `junction` (Windows-specific reparse point).
<disk_name> The configured name of the disk (string).
<subpath> The path of the link relative to the disk's root (escaped).
<linkto> The target path of the link (escaped).

Summary Tags

These tags log final statistics about the entire listing operation.

summary:file_count:<count>
Logs the total number of regular files processed.
<count> The total number of files (uint).
summary:file_size:<size>
Logs the total size of all regular files processed.
<size> The cumulative size of all files (uint64, bytes).
summary:link_count:<count>
Logs the total number of links processed (hardlinks, symlinks, symdirs, junctions).
<count> The total number of links (uint).
summary:exit:ok
Indicates a successful completion of the listing operation. Note that if a fatal error happens, the program will abort, and you won't get this tag.

11 Command Dup Tags

This section describes the tags output with the `dup` command.

Duplicate Tags

These tags log information about detected duplicate files and provide a summary of the duplicate finding process. The content hash of the whole file is used to determine duplicates.

dup:<diskname1>:<file_path1>:<diskname2>:<file_path2>:<size>: dup
Logs the information about a pair of duplicate files found. The first file listed is the one just processed, and the second file is the previously processed file that has the same content hash.
<diskname1> The configured name of the disk containing the newly processed duplicate file.
<file_path1> The path of the newly processed duplicate file relative to its disk's mount point (escaped).
<diskname2> The configured name of the disk containing the previously processed file that is the duplicate of `<file_path1>`.
<file_path2> The path of the previously processed duplicate file relative to its disk's mount point (escaped).
<size> The size of the duplicate file in bytes (uint64). This size corresponds to the file `<file_path2>`.

Summary Tags

These tags provide a final summary of the duplicate finding process.

summary:dup_count:<count>
Logs the total number of duplicate files found. A file is counted as a duplicate if its hash matches a hash already seen.
<count> The total count of duplicate files (uint).
summary:dup_size:<size>
Logs the total size of all duplicate files found. This size is the sum of the sizes of all files considered duplicates.
<size> The total size of duplicate files in gigabytes (uint64).
summary:exit:unique
Logs the final exit status indicating that no duplicate files were found. This tag is logged if `<count>` is zero.
summary:exit:dup
Logs the final exit status indicating that at least one duplicate file was found. This tag is logged if `<count>` is greater than zero.

12 Command Pool Tags

This section describes the tags output with the `pool` command.

summary:link_count:<count>
Logs the total number of links created (symlinks, junctions).
<count> The total number of links (uint).
summary:exit:ok
Indicates a successful completion of the pool operation. Note that if a fatal error happens, the program will abort, and you won't get this tag.

13 Command Rehash Tags

This section describes the tags output with the `rehash` command.

Summary Tags

These tags provide a final summary of the rehash scheduling process.

summary:exit:scheduled
Logs the final exit status indicating that a rehash operation has been successfully scheduled. The rehash will be performed incrementally in future `sync` or `scrub` commands.
summary:exit:already_in_progress
Logs the final exit status indicating that a rehash is already in progress and cannot be scheduled again. This causes the program to exit with a fatal error.
summary:exit:not_required
Logs the final exit status indicating that the current hash algorithm is already the `best hash` for the platform, and thus a rehash is not required. This causes the program to exit with a fatal error.

14 Command Smart Tags

This section describes the tags output with the `smart` command.

Note that a `<disk_name>` may be associated with more `<device_file>`, in case the logical disk uses more physical disks. In such a case, you'll see multiple tags for the same `<disk_name>` but with different `<device_file>`.

SMART Attributes

Tags logging specific disk identification and raw SMART attribute values.

smart:<device_file>:<disk_name>
Logs the start of the SMART report for a device.
<device_file> The file path of the device (e.g., /dev/sdb).
<disk_name> The configured name of the disk.
attr:<device_file>:<disk_name>:serial:<serial_number>
Logs the disk's serial number.
<serial_number> The disk's serial number (escaped).
attr:<device_file>:<disk_name>:vendor:<vendor>
Logs the disk's vendor string.
<vendor> The disk's vendor identifier (escaped).
attr:<device_file>:<disk_name>:model:<model>
Logs the disk's model string.
<model> The disk's model identifier (escaped).
attr:<device_file>:<disk_name>:afr:<afr_value>:<afr_prob>
Logs the estimated Annual Failure Rate (AFR) and the probability of one failure in the next year based on SMART attributes. The AFR is calculated using the maximum rate reported by specific SMART attributes (5, 187, 188, 197, 198).
<afr_value> The computed Annual Failure Rate (double).
<afr_prob> The probability of one or more failures in the next year (double).
attr:<device_file>:<disk_name>:size:<size_bytes>
Logs the size of the disk.
<size_bytes> The disk size in bytes (uint64).
attr:<device_file>:<disk_name>:error:<error_count>
Logs the raw value of the total error count (e.g., from SMART attribute 199, if used for the report).
<error_count> The total error count (uint64).
attr:<device_file>:<disk_name>:rotationrate:<rate>
Logs the disk's rotation rate. A value of 0 indicates an SSD.
<rate> The rotation rate (uint64, RPM).
attr:<device_file>:<disk_name>:flags:<flags_decimal>:<flags_hex>
Logs the SMART status flags from the utility (e.g., smartctl).
<flags_decimal> The raw flags value (uint64, decimal).
<flags_hex> The raw flags value (uint64, hexadecimal).
attr:<device_file>:<disk_name>:<id>:<value_decimal>:<value_hex>
Logs the raw value of any assigned SMART attribute.
<id> The SMART attribute ID (uint).
<value_decimal> The raw attribute value (uint64, decimal).
<value_hex> The raw attribute value (uint64, hexadecimal).

Summary

Tags logging the overall failure probabilities for the array.

summary:array_failure:<array_afr>:<array_prob>
Logs the total estimated failure rate for the entire array (sum of individual disk AFRs) and the probability of at least one disk failure in the next year.
<array_afr> The sum of AFRs of all disks in the array (double).
<array_prob> The probability of at least one disk failure in

the next year (double).

15 Command Probe Tags

This section describes the tags output with the `probe` command.

Note that a `<disk_name>` may be associated with more `<device_file>`, in case the logical disk uses more physical disks. In such a case, you'll see multiple tags for the same `<disk_name>` but with different `<device_file>`.

Device Power State

Tags used to report the power state of each device.

probe:<device_file>:<disk_name>:<power_state>
Logs the detected power state of a device.
<device_file> The file path of the device (e.g., /dev/sdb).
<disk_name> The configured name of the disk.
<power_state> The numerical power state: 0: Unknown, 1: StandBy, 2: Active.

16 Error Tags

These tags report specific errors that occur on data disks during the commands that access files and parities.

error:<block>:<disk_name>:<file>:<msg>
Logs file access errors (open, read, file changed) during the data disk read operation for parity calculation or verification.
<block> The zero-based index of the block where the error occurred (uint).
<disk_name> The name of the data disk.
<file> The path (relative to the disk mount point) of the file containing the block (escaped).
<msg> A descriptive message indicating the nature of the error (e.g., `Open/Read/Write EIO error`, `Open/Read/Write error`, `Data error at position <pos>, diff bits <diff>/<bits>`).
parity_error:<block>:<level>:<msg>
Logs errors during parity disk read or write operations.
<block> The zero-based index of the block where the error occurred (uint).
<level> The configuration name of the parity level (e.g., `parity`, `2-parity`).
<msg> A descriptive message indicating the nature of the error (e.g., `Read/Write EIO error`, `Read/Write error`, `Data error, diff bits <diff>/<bits>`).
hardlink_error:<disk_name>:<link_path>:<target_path>:<msg>
Indicates an error when attempting to access a hard link.
<disk_name> The name of the disk.
<link_path> The hard link path relative to disk root (escaped).
<target_path> The target path of the hard link (escaped).
<msg> A descriptive message indicating the nature of the error (e.g., `Hardlink stat error`, `Hardlink error for not regular file`, `Hardlink to stat error`, `Hardlink-to error for not regular file`, `Hardlink mismatch for different inode`).
symlink_error:<disk_name>:<link_path>:<msg>
Indicates an error when attempting to access a symbolic link.
<disk_name> The name of the disk.
<link_path> The symlink path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the error (e.g., `Symlink read error`, `Symlink data error '<actual>' instead of '<expected>'`).
dir_error:<disk_name>:<dir_path>:<msg>
Indicates an error when attempting to access a directory.
<disk_name> The name of the disk.
<dir_path> The directory path relative to disk root (escaped).
<msg> A descriptive message indicating the nature of the error (e.g., `Dir stat error`, `Dir error for not directory`).
outofparity:<disk_name>:<file_path>
Logs that a file's blocks extend beyond the available parity space, indicating that the parity files are too small to protect all data. This occurs when data requires more parity than is available on the parity disk(s) and is a critical warning.
<disk_name> The name of the disk containing the file.
<file_path> The file path relative to the disk root (escaped).