[zfs-discuss] Abysmal performance with zvols.

David Yu david.yu.ftw at gmail.com
Wed Mar 28 22:40:43 EDT 2012


Some numbers on a mirrored 2*2TB WD20EARX on N40L microserver with Ubuntu
11.10 zfsonlinx latest beta:

$ dd if=/dev/zero of=output1 bs=1M count=10000
10485760000 bytes (10 GB) copied, 98.7685 s, 106 MB/s

$ dd if=output1 of=/dev/null bs=1M
10485760000 bytes (10 GB) copied, 45.742 s, 229 MB/s

On Sat, Mar 10, 2012 at 2:40 PM, Christ Schlacta <aarcane at aarcane.org>wrote:

> Daily ppa on ubuntu oneiric.
>
>
> On 3/9/2012 22:38, Richard Yao wrote:
>
>> Which version of ZFSOnLinux are you using on which distribution?
>>
>> On Fri, Mar 9, 2012 at 10:14 PM, Christ Schlacta<aarcane at aarcane.org>
>>  wrote:
>>
>>> I'm getting abysmal read and write performance with zvols compared to
>>> file systems (and files) on zfs.  Here's some example read data and some
>>> superfluous info about my system.  I ran all the commands one right
>>> after another, just now.  I canceled the first read after approximately
>>> 5 minutes.
>>>
>>> aarcane at density:~$ sudo aptitude safe-upgrade
>>> No packages will be installed, upgraded, or removed.
>>> 0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
>>> Need to get 0 B of archives. After unpacking 0 B will be used.
>>>
>>> aarcane at density:~$ sudo dd if=/dev/zvol/tank/osximg of=/dev/null bs=8192
>>> ^C352479+0 records in
>>> 352478+0 records out
>>> 2887499776 bytes (2.9 GB) copied, 277.439 s, 10.4 MB/s
>>> aarcane at density:~$ sudo dd if=/tank/videos/Movies/Jay\ and\ Silent\ Bob\
>>> Strike\ Back.mkv of=/dev/null bs=8192
>>> 2305553+1 records in
>>> 2305553+1 records out
>>> 18887093942 bytes (19 GB) copied, 59.6668 s, 317 MB/s
>>> aarcane at density:~$ sudo zpool list
>>> NAME        SIZE  ALLOC   FREE    CAP  DEDUP  HEALTH  ALTROOT
>>> downloads   931G   725G   206G    77%  1.00x  ONLINE  -
>>> tank       5.46T  4.59T   888G    84%  2.45x  ONLINE  -
>>> aarcane at density:~$ sudo zpool status
>>>   pool: downloads
>>>  state: ONLINE
>>>  scan: scrub repaired 0 in 6h17m with 0 errors on Sat Jan  7 16:53:35
>>> 2012
>>> config:
>>>
>>>         NAME                      STATE     READ WRITE CKSUM
>>>         downloads                 ONLINE       0     0     0
>>>           wwn-0x50000f00060b8097  ONLINE       0     0     0
>>>
>>> errors: No known data errors
>>>
>>>   pool: tank
>>>  state: ONLINE
>>>  scan: scrub repaired 0 in 9h11m with 0 errors on Fri Mar  9 03:53:26
>>> 2012
>>> config:
>>>
>>>         NAME                        STATE     READ WRITE CKSUM
>>>         tank                        ONLINE       0     0     0
>>>           raidz1-0                  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc3c27c  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc4d6e5  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc1c2bd  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc5f81d  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc6295c  ONLINE       0     0     0
>>>             wwn-0x5000cca35dc4abb5  ONLINE       0     0     0
>>>
>>> errors: No known data errors
>>> aarcane at density:~$ uname -a
>>> Linux density 3.0.0-16-server #29-Ubuntu SMP Tue Feb 14 13:08:12 UTC
>>> 2012 x86_64 x86_64 x86_64 GNU/Linux
>>> aarcane at density:~$
>>>
>>>
>


-- 
When the cat is away, the mouse is alone.
- David Yu
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