ZFS L2arc 16.0E size

[Frank de Bot (lists)]

I've done some extra tests:

I used a different ssd (samsung 840 pro), same result. I checkout the
commitpoint '273060' and build another kernel, uname now says:

'FreeBSD nas 10.1-PRERELEASE FreeBSD 10.1-PRERELEASE #1 r273060: Sat Feb
21 18:42:08 UTC 2015     user at nas:/usr/obj/usr/src/sys/GENERIC  amd64

Still same result.

cache                        -      -      -      -      -      -
  gpt/l2arc1             68.0G  16.0E      4    165  23.2K  19.3M
  gpt/l2arc2             68.0G  16.0E      5    162  24.8K  18.6M

This already occures after 1 tot 2 hours when transferring a lot of data
via rsync to the dataset.
Is it worth to try hooking up the ssd to another controller (current on
a LSI MegaRAID SAS 9211-4i)


Regards,

Frank de Bot



Frank de Bot wrote:
> I did remove and added devices again, with:
> 
> 'zpool remove tank gpt/l2arc1 gpt/l2arc2'
> and then
> 'zpool add tank cache gpt/l2arc1 gpt/l2arc2'
> 
> I left it running overnight and the same situation occured.
> 
> cache                        -      -      -      -      -      -
>   gpt/l2arc1              175G  16.0E     11    106  55.5K  9.75M
>   gpt/l2arc2              167G  16.0E     14    107  68.8K  9.81M
> 
> For faster filling of the l2arc I also had 2 systcl's set:
> 
> vfs.zfs.l2arc_write_max: 33554432
> vfs.zfs.l2arc_write_boost: 33554432
> 
> I do not plan to use this for production, only in testing.
> 
> 
> Regards,
> 
> Frank de Bot
> Steven Hartland wrote:
>> IIRC this was fixed by r273060, if your remove your cache device and
>> then add it back I think you should be good.
>>
>> On 16/02/2015 00:23, Frank de Bot (lists) wrote:
>>> Hello,
>>>
>>> I have a FreeBSD 10.1 system with a raidz2 zfs configuration with 2ssd's
>>> for l2arc . It is running '10.1-STABLE FreeBSD 10.1-STABLE #0 r278805'
>>> Currently I'm running tests before it can go to production, but I have
>>> the following issue. After a while the l2arc devices indicate 16.0E free
>>> space and it starts 'consuming' more than it can hold
>>>
>>> cache                        -      -      -      -      -      -
>>>    gpt/l2arc1              107G  16.0E      0      2      0  92.7K
>>>    gpt/l2arc2             68.3G  16.0E      0      1      0  60.8K
>>>
>>> It ran good for a while, where data was removed from cache so it could
>>> be filled with newer data. (Free space was always around 200/300Mbytes).
>>>
>>> I've read about similar issues, which should be fixed in different
>>> commits, but I'm running the latest stable 10.1 kernel right now. (One
>>> of the last similar issue is:
>>> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=197164 )
>>> Another similar issue reported at FreeNAS
>>> https://bugs.freenas.org/issues/5347 suggested it would be a hardware
>>> issue, but I have 2 servers which experience the same problem. One has a
>>> Crucial M500 drive and the other a M550. Both have a 64G partition voor
>>> l2arc.
>>>
>>> What is really going on here?
>>>
>>>
>>> Regards,
>>>
>>>
>>> Frank de Bot
>>> _______________________________________________
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>>
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