about the xfs performance

[Eric Sandeen]

On 4/11/16 11:10 AM, Emmanuel Florac wrote:
> Le Mon, 11 Apr 2016 22:14:06 +0800
> Songbo Wang <hack.coo at gmail.com> écrivait:
> 
>>      mkfs: mkfs.xfs /dev/hioa2 -f -n size=64k -i size=512 -d
>> agcount=40 -l size=1024m.
>>      mount: mount /dev/hioa2 /mnt/  -t xfs -o
>> rw,noexec,nodev,noatime,nodiratime,nobarrier,discard,inode64,logbsize=256k,delaylog
>> I use the following command to test iops: fio -ioengine=libaio -bs=4k
>> -direct=1 -thread -rw=randwrite -size=50G -filename=/mnt/test
>> -name="EBS 4KB randwrite test" -iodepth=64 -runtime=60
>> The results is normal at the beginning which is about 210k±，but some
>> seconds later, the results down to 19k±.
> 
> You should first try default mkfs settings, with default mount options.

Agreed.  Where did that set of options come from, in any case?

-Eric

> Normally mkfs.xfs should initiate a TRIM on the SSD, therefore
> performance should remain predictable.
> 
> What model of SSD card are you using? With an HGST NVMe SN1x0 I've got
> very consistent results (no degradation with time).
>