re[2]: [rdiff-backup-users] ACLS

[dean gaudet]

On Tue, 11 Feb 2003, Greg Freemyer wrote:

> Is there any way to have the backup be compressed?

there is an ancient compression patch for ext2 ... but nothing recent
and/or for ext3.

compression would be OK, but there may be performance problems doing that
-- the backup host has to generate rolling checksums for the rsync
algorithm.  with the new metadata files that ben has we could in theory
save such calculations and reduce the overhead necessary to decompress
prior to calculating them...

fwiw, here are my session statistics:

--------------[ Average of 87 stat files ]--------------
ElapsedTime 16926.60 (4 hours 42 minutes 6.60 seconds)
SourceFiles 720256.965517
SourceFileSize 75469552289.6 (70.3 GB)
MirrorFiles 719559.954023
MirrorFileSize 75358559485.8 (70.2 GB)
NewFiles 3593.86206897
NewFileSize 438904787.31 (419 MB)
DeletedFiles 2896.85057471
DeletedFileSize 347248424.931 (331 MB)
ChangedFiles 3148.83908046
ChangedSourceSize 3656141271.91 (3.41 GB)
ChangedMirrorSize 3636804830.44 (3.39 GB)
IncrementFiles 9640.56321839
IncrementFileSize 439144925.851 (419 MB)
TotalDestinationSizeChange 550137729.701 (525 MB)
Errors 315
--------------------------------------------------------

(the errors are due to an active daemon modifying files underneath
rdiff-backup -- i really want to use LVM snapshot volumes to avoid doing
rdiff-backup on a live filesystem, but there are performance issues with
linux raid5 and LVM snapshotting... not solved until the 2.5 kernels,
which as you can imagine i'm not running on a production system yet :)

# df /backup
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/neemlark_vg/backup
                     165139820 138949484  17801728  89% /backup
# df -i /backup
Filesystem            Inodes   IUsed   IFree IUse% Mounted on
/dev/neemlark_vg/backup
                     20971520 2640494 18331026   13% /backup


so that's 87 days worth of increments plus the source files in 133G...
and the source files are 70G.  there's a handful of other small systems
backed up on /backup as well, so it's probably more like 120G for 70G
plus 87 days.

all in all given the cost of IDE raids i'm not worried so much about
getting compression going, but your situation may be different.

-dean