Reducing ZFS blocksize to improve Cyrus write performance ?

[Eric Luyten]

On Tue, August 10, 2010 4:06 pm, Gary Mills wrote:
> On Mon, Aug 09, 2010 at 09:03:44PM +0200, Pascal Gienger wrote:
>
>> Am 09.08.10 19:46, schrieb Vincent Fox:
>>
>>> * Turn off ZFS cache flushing
>>> set zfs:zfs_nocacheflush = 1
>>
>> For hardware (fiberchannel, iSCSI, SSA, ...) arrays with their own Cache
>> this is a must.
>
> Only if the SAN device handles cache flush requests incorrectly.
> It should consider a write to battery-backed memory as a write to
> permanent storage, and manage its own writes to disk from there.


Folks,


Be aware that the zfs_nocacheflush parameter is global and thus applies
to all ZFS filesystems on your server, local (system) disks included ...

http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Cache_Flushes

offers extra reading material.


Pascal, Vincent and Gary, I have been ploughing your valuable comments back
into our development team's discussions ! Thank you.


Eric Luyten.