[OmniOS-discuss] Slow zfs writes

[Eric Sproul]

You still haven't said how you know that performance has dropped 30x.
Where are the numbers?

On Mon, Feb 11, 2013 at 11:33 AM, Ram Chander <ramquick at gmail.com> wrote:
> I am not sure what happened on Jan 5. I havent run scrub or replaced devices
> for more than 3 months. The underlying hardware is Dell Md1200 which has 48
> disks.
> How to recover from this ? I had tried rebooting  but issue comes back.
>
>
> On Mon, Feb 11, 2013 at 8:14 PM, Eric Sproul <esproul at omniti.com> wrote:
>>
>> On Mon, Feb 11, 2013 at 7:48 AM, Ram Chander <ramquick at gmail.com> wrote:
>> > Hi,
>> >
>> > My OI box is expreiencing slow zfs writes ( around 30 times slower ).
>> > iostat
>> > reports below error though pool is healthy. This is happening in past 4
>> > days
>> > though no change was done to system. Is the hard disks faulty ?
>> > Please help.
>>
>> How have you measured this 30x drop in performance?  You haven't
>> provided any data.
>>
>>
>> > c4t0d0           Soft Errors: 0 Hard Errors: 5 Transport Errors: 0
>> > Vendor: iDRAC    Product: Virtual CD       Revision: 0323 Serial No:
>> > Size: 0.00GB <0 bytes>
>> > Media Error: 0 Device Not Ready: 5 No Device: 0 Recoverable: 0
>> > Illegal Request: 1 Predictive Failure Analysis: 0
>>
>> I wouldn't worry about errors here.  This is a virtual device provided
>> by your server's lights-out management system.
>>
>>
>> > root at host:~# fmadm faulty
>> > --------------- ------------------------------------  --------------
>> > ---------
>> > TIME            EVENT-ID                              MSG-ID
>> > SEVERITY
>> > --------------- ------------------------------------  --------------
>> > ---------
>> > Jan 05 08:21:09 7af1ab3c-83c2-602d-d4b9-f9040db6944a  ZFS-8000-HC
>> > Major
>> >
>> > Host        : host
>> > Platform    : PowerEdge-R810
>> > Product_sn  :
>> >
>> > Fault class : fault.fs.zfs.io_failure_wait
>> > Affects     : zfs://pool=test
>> >                   faulted but still in service
>> > Problem in  : zfs://pool=test
>> >                   faulted but still in service
>> >
>> > Description : The ZFS pool has experienced currently unrecoverable I/O
>> >                     failures.  Refer to
>> > http://illumos.org/msg/ZFS-8000-HC
>> > for
>> >               more information.
>> >
>> > Response    : No automated response will be taken.
>> >
>> > Impact      : Read and write I/Os cannot be serviced.
>> >
>> > Action      : Make sure the affected devices are connected, then run
>> >                     'zpool clear'.
>>
>> What has happened since January 5?  The pool appears fine now.  Did
>> you run a scrub?  Replace devices?  Reboot?  It looks like ZFS
>> encountered an underlying problem with the hardware.
>>
>> Eric
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>
>