NAME¶
zstream —
manipulate ZFS send streams
SYNOPSIS¶
zstream |
dump [-Cvd]
[file] |
zstream |
decompress [-v]
[object,offset[,type...]] |
zstream |
token resume_token |
zstream |
recompress [-l
level] algorithm |
DESCRIPTION¶
The
zstream
utility manipulates ZFS send streams output by the
zfs send
command.
zstream dump
[-Cvd] [file]- Print information about the specified send stream, including headers and
record counts. The send stream may either be in the specified
file, or provided on standard input.
-C- Suppress the validation of checksums.
-v- Verbose. Print metadata for each record.
-d- Dump data contained in each record. Implies verbose.
The zstreamdump alias is provided for
compatibility and is equivalent to running
zstream dump.
zstream token
resume_token- Dumps zfs resume token information
zstream
decompress [-v]
[object,offset[,type...]]- Decompress selected records in a ZFS send stream provided on standard
input, when the compression type recorded in ZFS metadata may be
incorrect. Specify the object number and byte offset of each record that
you wish to decompress. Optionally specify the compression type. Valid
compression types include off,
gzip,
lz4,
lzjb,
zstd,
and zle.
The default is lz4. Every record for that object
beginning at that offset will be decompressed, if possible. It may not be
possible, because the record may be corrupted in some but not all of the
stream's snapshots. Specifying a compression type of off
will change the stream's metadata accordingly, without attempting
decompression. This can be useful if the record is already uncompressed
but the metadata insists otherwise. The repaired stream will be written to
standard output.
-v- Verbose. Print summary of decompressed records.
zstream redup
[-v] file- Deduplicated send streams can be generated by using the
zfs send
-D command. The ability to send deduplicated send
streams is deprecated. In the future, the ability to receive a
deduplicated send stream with zfs
receive will be removed. However, deduplicated
send streams can still be received by utilizing
zstream redup.
The zstream
redup command is provided a
file containing a deduplicated send stream, and
outputs an equivalent non-deduplicated send stream on standard output.
Therefore, a deduplicated send stream can be received by running:
# zstream
redup DEDUP_STREAM_FILE |
zfs receive
…
-v- Verbose. Print summary of converted records.
zstream recompress
[-l level]
algorithm- Recompresses a send stream, provided on standard input, using the provided
algorithm and optional level, and writes the modified stream to standard
output. All WRITE records in the send stream will be recompressed, unless
they fail to result in size reduction compared to being left uncompressed.
The provided algorithm can be any valid value to the
compress property. Note that encrypted send
streams cannot be recompressed.
-l
level- Specifies compression level. Only needed for algorithms where the
level is not implied as part of the name of the algorithm (e.g. gzip-3
does not require it, while zstd does, if a non-default level is
desired).
EXAMPLES¶
Heal a dataset that was corrupted due to OpenZFS bug #12762.
First, determine which records are corrupt. That cannot be done
automatically; it requires information beyond ZFS's metadata. If object
128 is
corrupted at offset
0 and is
compressed using lz4, then run this command:
# zfs send -c … | zstream decompress 128,0,lz4 | zfs recv …
