FreeBSD ZFS

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Background

I had some ideas regarding using ZFS for some NSM-related duties.. mainly employing the 'compression' features
that it natively offers. My tests were done using FreeBSD 8.0-RC1/amd64 on a Dell 1950..

Implementation

I have 2*500GB WD SATA 7200RPM drives with a Dell PERC5/i (mfi(4)) keeping them in RAID configuration.
My testing machine has both disks in RAID1, in production they'll run with RAID0 to maximize space, since
data integrity isn't really important (best-effort application).
I have 1 spare partition '/dev/mfid0s1g' of a bit over 400GB to play with.
I'm testing using 3 different compression algorithms: "lzjb", "gzip-6" and "gzip-9".

Create the tank:

 ^:root@viola:~# zpool create tank /dev/mfid0s1g

Create 3 filesystems using the varying algorithms:

 ^:root@viola:~# zfs create -o compression=lzjb -o mountpoint=/tank/lzjb -o atime=off -o quota=20G tank/lzjb
 ^:root@viola:~# zfs create -o compression=gzip-6 -o mountpoint=/tank/gzip-6 -o atime=off -o quota=20G tank/gzip-6
 ^:root@viola:~# zfs create -o compression=gzip-9 -o mountpoint=/tank/gzip-9 -o atime=off -o quota=20G tank/gzip-9

"Benchmarks" using 'dd'

lzjb

 ^:root@viola:~# zfs create -o compression=lzjb -o mountpoint=/tank/lzjb -o atime=off -o quota=20G tank/lzjb
 ^:root@viola:/tank/lzjb# dd if=/dev/zero of=test.20G bs=1G count=20
 20+0 records in
 20+0 records out
 21474836480 bytes transferred in 40.658224 secs (528179405 bytes/sec)
 ^:root@viola:/tank/lzjb# dd if=/dev/urandom of=test.16M bs=16M count=1
 1+0 records in
 1+0 records out
 16777216 bytes transferred in 0.300089 secs (55907489 bytes/sec)

gzip-6

 ^:root@viola:/# zfs create -o compression=gzip -o mountpoint=/tank/gzip-6 -o atime=off -o quota=20G tank/gzip-6
 ^:root@viola:/tank/gzip-6# dd if=/dev/zero of=test.20G bs=1G count=20
 20+0 records in
 20+0 records out
 21474836480 bytes transferred in 40.611659 secs (528785009 bytes/sec)
 ^:root@viola:/tank/gzip-6# dd if=/dev/urandom of=test.16M bs=16M count=1
 1+0 records in
 1+0 records out
 16777216 bytes transferred in 0.299824 secs (55956881 bytes/sec)

gzip-9

 ^:root@viola:/tank/lzjb# zfs create -o compression=gzip-9 -o mountpoint=/tank/gzip-9 -o atime=off -o quota=20G tank/gzip-9
 ^:root@viola:/tank/gzip-9# dd if=/dev/zero of=test.20G bs=1G count=20
 20+0 records in
 20+0 records out
 21474836480 bytes transferred in 40.541599 secs (529698803 bytes/sec)
 ^:root@viola:/tank/gzip-9# dd if=/dev/urandom of=test.16M bs=16M count=1
 1+0 records in
 1+0 records out
 16777216 bytes transferred in 0.299950 secs (55933397 bytes/sec)

Summary

So, it doesn't seem that in this brief bit of testing that there is any appreciable speed/time
differences... but, its also not a very comprehensive bit of testing.. maybe some bonnie testing
at a later date?

Results from 'df'

Contents of /tank/[compressedfs]:

2*12M (/boot/kernel/kernel: 12087259)
1*16M (/dev/urandom)
1*20G (/dev/zero)

 ^:root@viola:/tank/gzip-6# df -h /tank /tank/lzjb /tank/gzip-6 /tank/gzip-9
 Filesystem       Size    Used   Avail Capacity  Mounted on
 tank             421G      0B    421G     0%    /tank
 tank/lzjb         20G     32M     20G     0%    /tank/lzjb
 tank/gzip-6       20G     26M     20G     0%    /tank/gzip-6
 tank/gzip-9       20G     26M     20G     0%    /tank/gzip-9

 ^:root@viola:/tank/gzip-9# df /tank /tank/lzjb /tank/gzip-6 /tank/gzip-9
 Filesystem    1K-blocks    Used     Avail Capacity  Mounted on
 tank          441691520       0 441691520     0%    /tank
 tank/lzjb      20971520   33152  20938368     0%    /tank/lzjb
 tank/gzip-6    20971520   26752  20944768     0%    /tank/gzip-6
 tank/gzip-9    20971520   26752  20944768     0%    /tank/gzip-9

Production System

Introduction

I have 880GB to work with, so:

 ^:root@seau:/# zpool create tank /dev/mfid0s1g

Once the tank is there, I opted to save a bit off the top and tried both 'gzip-6' and 'lzjb'..

'gzip-6' turns out to cause too long of a buffer-sync-to-disk, and makes the system block while it does so.
'lzjb' does not seem to do this, so it is what I went with in the end.

 ^:root@seau:/# zfs create -o compression=lzjb -o mountpoint=/nsm -o atime=off -o quota=850G

I'm running 'daemonlogger' like this:

 ^:root@seau:/# daemonlogger -d -i bce1 -l /nsm/bce1 -u nsm -g nsm -r -s 1073741824 -m 840 -P /nsm/run -S 65535

Overall, this means 880GB in the tank, 850GB in the tank/nsm pool, 30GB leftover in the tank,
and daemonlogger makes 840 1GB files, so 10GB leftover in the mount (/nsm).

Random Statistic

 ^:root@seau:/nsm/bce1# zpool iostat
                capacity     operations    bandwidth
 pool         used  avail   read  write   read  write
 ----------  -----  -----  -----  -----  -----  -----
 tank        6.89G   873G      0     62  3.76K  7.41M