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.IX Title "nbdkit-lzip-filter 1"
.TH nbdkit-lzip-filter 1 2026-09-01 nbdkit-1.49.3 NBDKIT
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.SH NAME
nbdkit\-lzip\-filter \- nbdkit lzip filter
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\& nbdkit \-\-filter=lzip file FILENAME.lz
.Ve
.PP
.Vb 1
\& nbdkit \-\-filter=lzip curl https://example.com/FILENAME.lz
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
\&\f(CW\*(C`nbdkit\-lzip\-filter\*(C'\fR is a filter for \fBnbdkit\fR\|(1) which transparently
decompresses an \fBlzip\fR\|(1)\-compressed file.  You can place this filter
on top of \fBnbdkit\-file\-plugin\fR\|(1) to decompress a local \fI.lz\fR file,
or on top of other plugins such as \fBnbdkit\-curl\-plugin\fR\|(1):
.PP
.Vb 1
\& nbdkit curl \-\-filter=lzip https://example.com/disk.lz
.Ve
.PP
With \fBnbdkit\-partition\-filter\fR\|(1) it can be used to mount a specific
partition of a compressed disk image:
.PP
.Vb 2
\& nbdkit curl \-\-filter=partition \-\-filter=lzip \e
\&        https://example.com/disk.img.lz partition=2
.Ve
.PP
The filter only supports read\-only connections.
.PP
\&\fBNote\fR that this filter was made primarily for multi\-member files.
Single\-member files are currently only supported up to a size of
\&\f(CW\*(C`lzip\-max\-block\*(C'\fR and their contents are kept in memory.
.SS "Single\-member files and multi\-member files"
.IX Subsection "Single-member files and multi-member files"
An lzip\-compressed file consists of one or more members, with each
member containing an LZMA stream and some metadata.  Most lzip files
consist of only a single member holding all of the compressed data.
You can find out the number of members in an lzip file by doing:
.PP
.Vb 5
\& $ lzip \-\-list \-\-verbose lfs.img.lz
\&   dict   memb  trail   uncompressed   compressed   saved  name
\&   8 MiB     1      0    10737418240   1808781538  83.15%  lfs.img.lz
\&           ↑↑↑
\&          members
.Ve
.PP
Seeking an lzip file is done by seeking directly to the lower member
boundary, then decompressing data until the precise byte is reached.
Because of this, \fBsingle\-member files are not seekable and must be\fR
\&\fBdecompressed entirely\fR.
.SS "Getting the best random access performance"
.IX Subsection "Getting the best random access performance"
Use the \fBplzip\fR\|(1) parallel compressor with the \fI\-\-data\-size\fR option
set to a small\-ish block size.  plzip first splits the input file into
\&\fIfixed\-size\fR data blocks before compressing each block as a separate
member.  For example this is the same image as above compressed with
plzip on default settings, resulting in a block size of 16 MiB:
.PP
.Vb 5
\& $ lzip \-\-list \-\-verbose lfs.img.lz
\&   dict   memb  trail   uncompressed   compressed   saved  name
\&   8 MiB   640      0    10737418240   1839569039  82.87%  lfs.img.lz
\&           ↑↑↑
\&          members
.Ve
.PP
This file allows \fBrandom access in constant time\fR.  At most 16 MiB
will have to be decompressed to seek to any byte.  The position of the
member that needs to be decompressed can be computed directly.
.PP
If you don\*(Aqt have access to plzip, you can achieve the same result
using the \fBsplit\fR\|(1) utility together with regular lzip.
.PP
.Vb 3
\& $ split \-b 16m disk.img disk.img.part
\& $ lzip disk.img.part*
\& $ cat disk.img.part*.lz > disk.img.lz
.Ve
.PP
Do \fInot\fR just use lzip with the \fI\-\-member\-size\fR option, since that
option refers to member size, not data block size.
.SS "Multi\-member files with variable\-size data blocks"
.IX Subsection "Multi-member files with variable-size data blocks"
Some ways of creating multi\-member lzip files, such as the
\&\fI\-\-member\-size\fR option or the \fBtarlz\fR\|(1) utility, result in data
blocks of varying sizes.  In this case, seeking requires a binary
search on the member index and random access takes logarithmic time.
.SH PARAMETERS
.IX Header "PARAMETERS"
.IP \fBlzip\-max\-block=\fRSIZE 4
.IX Item "lzip-max-block=SIZE"
The maximum block size that the filter will read.  The filter will
refuse to read lzip files that contain any data block larger than this
size.  This value refers to size of the uncompressed block, not the
size of the member holding it.
.Sp
This parameter is optional.  If not specified it defaults to 512M.
.IP \fBlzip\-max\-depth=\fRN 4
.IX Item "lzip-max-depth=N"
Maximum number of blocks stored in the LRU block cache.
.Sp
This parameter is optional.  If not specified it defaults to 8.
.Sp
The filter may allocate up to
maximum\ block\ size\ in\ file\ ×\ maxdepth
bytes of memory \fIper connection\fR.
.SH FILES
.IX Header "FILES"
.ie n .IP \fR\fI$filterdir\fR\fI/nbdkit\-lzip\-filter.so\fR 4
.el .IP \fR\f(CI$filterdir\fR\fI/nbdkit\-lzip\-filter.so\fR 4
.IX Item "$filterdir/nbdkit-lzip-filter.so"
The filter.
.Sp
Use \f(CW\*(C`nbdkit \-\-dump\-config\*(C'\fR to find the location of \f(CW$filterdir\fR.
.SH VERSION
.IX Header "VERSION"
\&\f(CW\*(C`nbdkit\-lzip\-filter\*(C'\fR first appeared in nbdkit 1.42.  It is derived
from \f(CW\*(C`nbdkit\-xz\-filter\*(C'\fR which first appeared in nbdkit 1.10.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBnbdkit\fR\|(1),
\&\fBnbdkit\-filter\fR\|(3),
\&\fBnbdkit\-curl\-plugin\fR\|(1),
\&\fBnbdkit\-file\-plugin\fR\|(1),
\&\fBnbdkit\-bzip2\-filter\fR\|(1),
\&\fBnbdkit\-gzip\-filter\fR\|(1),
\&\fBnbdkit\-partition\-filter\fR\|(1),
\&\fBnbdkit\-xz\-filter\fR\|(1),
\&\fBlzip\fR\|(1),
\&\fBplzip\fR\|(1),
\&\fBtarlz\fR\|(1).
.SH AUTHORS
.IX Header "AUTHORS"
Jan Felix Langenbach
.PP
Richard W.M. Jones
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright Jan Felix Langenbach
.PP
Copyright Red Hat
.SH LICENSE
.IX Header "LICENSE"
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
.IP \(bu 4
Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
.IP \(bu 4
Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
.IP \(bu 4
Neither the name of Red Hat nor the names of its contributors may be
used to endorse or promote products derived from this software without
specific prior written permission.
.PP
THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS \*(Aq\*(AqAS IS\*(Aq\*(Aq AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.