ZFSKnownProblems - needs revision?

Miroslav Lachman 000.fbsd at quip.cz
Wed Apr 8 21:59:23 UTC 2009

Ivan Voras wrote:

> Ivan Voras wrote:
>>* Are the issues on the list still there?
>>* Are there any new issues?
>>* Is somebody running ZFS in production (non-trivial loads) with
>>success? What architecture / RAM / load / applications used?
>>* How is your memory load? (does it leave enough memory for other services)
> also: what configuration (RAIDZ, mirror, etc.?)

I have two production servers with ZFS.

First is HP ProLiant ML110 G5 with 4x 1TB SATA Samsung drives in RAIDZ + 
5GB RAM running
Root is on USB flash drive with UFS, main storage is on ZFS.

# zfs list
NAME                              USED  AVAIL  REFER  MOUNTPOINT
tank                             1.34T  1.33T  29.9K  /tank
tank/system                      1.04G  1.33T  28.4K  /tank/system
tank/system/tmp                  52.4K  1.33T  52.4K  /tmp
tank/system/usr                   611M  1.33T  95.0K  /tank/system/usr
tank/system/usr/obj              26.9K  1.33T  26.9K  /usr/obj
tank/system/usr/ports             443M  1.33T   214M  /usr/ports
tank/system/usr/ports/distfiles   105M  1.33T   105M  /usr/ports/distfiles
tank/system/usr/ports/packages    123M  1.33T   123M  /usr/ports/packages
tank/system/usr/src               168M  1.33T   168M  /usr/src
tank/system/var                   459M  1.33T   213K  /var
tank/system/var/db                421M  1.33T   420M  /var/db
tank/system/var/db/pkg            387K  1.33T   387K  /var/db/pkg
tank/system/var/log              37.8M  1.33T  37.8M  /var/log
tank/system/var/run              60.6K  1.33T  60.6K  /var/run
tank/vol0                        1.34T  1.33T  1.34T  /vol0

This server is storage for backups made every night by rsync from 10 
FreeBSD machines.
It takes about 1 hour every night to do rsync backup of all machines.
Rsync is used for "snapshots" with --link-dest= (each day has own 
directory and all unchenged files are hardlinked to previous day and I 
have history of two month back).
Backups are stored on /vol0 with compression enabled. (compression is 
enabled on /usr/ports, /usr/src, /var/db/pkg, /vol0)

# df -hi /vol0/
Filesystem    Size    Used   Avail Capacity  iused    ifree %iused 
Mounted on
tank/vol0     2.7T    1.3T    1.3T    50% 17939375 11172232   62%   /vol0

This backup server is in service from october 2008 with just one panic 
(kmem related). After proper loader.conf tuning it is working well.

# cat /boot/loader.conf
## ZFS tuning

                                               up 80+04:52:10  23:33:40
28 processes:  1 running, 27 sleeping
CPU:  0.0% user,  0.0% nice,  0.0% system,  0.0% interrupt,  100% idle
Mem: 17M Active, 26M Inact, 1541M Wired, 328K Cache, 204M Buf, 3234M Free

The second server with ZFS is used as Jails hosting. It is buil on Sun 
Fire X2100 M2 with 2x 500GB SATA drives + 4GB RAM running
FreeBSD 7.1-STABLE amd64
from Wed Feb 11 09:56:08 CET 2009 (GENERIC kernel)
The hard drives are splitted to two slices, where first slice is used 
for gmirrored system (about 20GB) and the rest is used for ZFS mirror.

There are 5 Jails running. One with postfix as backup MX and BIND as 
slave DNS for little webhosting company. Few jails for webdevelopers 
(not heavily loaded), but last jail has 240GB of audio files for 
streaming throught Lighttpd with speed about 30Mbps.
There are some issues with Lighttpd in conjunction with ZFS - after 
about 30-60 minutes, Lighttpd decrease the speed to less than 7Mbps 
until it is restarted, then everything works well. The server has uptime 
56 days without any panic or other stability issues.
Another box with Lighttpd + UFS (not in jail) is serving same files by 
65Mbps without problem.
(Lighttpd problem may be related to jail instead of ZFS - I did not test 
it yet)

All jails are on compressed filesystems and there are some snapshots of 
each jail.

# cat /boot/loader.conf
## gmirror RAID1

## ZFS tuning

Miroslav Lachman

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