The timestamp matches the time it was built. It does not reflect the fact
that many months of development are excluded.

Mike

On Thu, Jul 26, 2018, 1:01 PM Len Weincier <[email protected]> wrote:

>
>
> On 26 Jul 2018, at 20:43, Mike Gerdts <[email protected]> wrote:
>
> On Thu, Jul 26, 2018 at 5:02 AM, Len Weincier <[email protected]> wrote:
>
>> On Wed, 2018-07-25 at 16:58 +0200, Len Weincier wrote:
>>
>> Hi
>>
>> We a very strange situation trying to upgrade to a newer smartos image
>> where the disk I/O is *very* slow.
>>
>> I have been working through the released images and the last one that
>> works 100% is 20180329T002644Z
>>
>> From 20180412T003259Z onwards, the release with the new zfs features like
>> spacemaps etc, the hosts become unusable in terms of disk i/o
>>
>> In our testing with the lab machine with only 128G ram we see no
>> pathologies.
>>
>> Hosts are running ALL SSDs (RAIDZ2), and Intel Gold 6150 x2 processors on
>> an SMC X11DPH-T board..
>> The lab machine with 128GB RAM has exactly the same processors, board,
>> and SSD-only setup - except for RAM..
>>
>> On a production machine with 768G ram and the newer image for eg zfs
>> create -V 10G zones/test takes 2 minutes while at the same time iostat is
>> showing the disks as relatively idle (%b = 10)
>>
>> For example inside an ubuntu kvm with postgres we are seeing 40% wait
>> time for any disk i/o and there are only 2 vm's running, underlying disks
>> essentially idle.
>>
>> Is there anything we can look at to get to the bottom of this as it
>> pretty critical and affecting our customers
>>
>>
>>
>> Hi
>>
>> I have managed to grab a bunch of stack traces from a dtrace script on
>> the fbt:zfs::entry events and generated a flamegraph while the system was
>> behaving badly
>>
>> https://static.prod.cloudafrica.net/out.svg
>>
>> This show a bunch of activity in the metaslab allocation if I read it
>> correctly ?
>>
>> Any ideas or anything I can look at please let me know.
>>
>> I have confirmed that this only occurs when the system is under i/o load.
>>
>>
> I've created a platform image based on 20180329T002644Z with this change
> that you mentioned removed.
>
> commit f78cdc34af236a6199dd9e21376f4a46348c0d56
> Author: Paul Dagnelie <[email protected]>
> Date:   Mon Feb 12 12:56:06 2018 -0800
>
>     9112 Improve allocation performance on high-end systems
>     Reviewed by: Matthew Ahrens <[email protected]>
>     Reviewed by: George Wilson <[email protected]>
>     Reviewed by: Serapheim Dimitropoulos <[email protected]>
>     Reviewed by: Alexander Motin <[email protected]>
>     Approved by: Gordon Ross <[email protected]>
>
>
> My testing has involved booting the iso under vmware and verifying that it
> could import an existing single disk pool and run the VMs on it.
>
> Can you give this PI a try?  As a reminder, my testing has been quite
> superficial.  I hope it won't eat your data, but can offer no guarantees.
>
>
> https://us-east.manta.joyent.com/mgerdts/public/pi/len/platform-20180726T160921Z.tgz
>
> https://us-east.manta.joyent.com/mgerdts/public/pi/len/platform-20180726T160921Z.iso
>
> https://us-east.manta.joyent.com/mgerdts/public/pi/len/platform-20180726T160921Z.usb.bz2
>
> Regards,
> Mike
>
>
> Hi Mike
>
> Do you mean its the latest image from master with that commit removed ?
> afaics that commit cam just after 20180329 ?
>
> I am away until monday and can give it a test then.
>
> Thanks
> Len
>
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