[pve-devel] ceph firefly in pve repos

[Alexandre DERUMIER]

>>That is about 250 IOPS? 

Yes, I got same result with fio and --sync=1


crucial m550
------------
#fio --filename=/dev/sdb --direct=1 --rw=write --bs=4k --numjobs=2 --group_reporting --invalidate=0 --name=ab --sync=1
bw=1249.9KB/s, iops=312

intel s3500
-----------
fio --filename=/dev/sdb --direct=1 --rw=write --bs=4k --numjobs=2 --group_reporting --invalidate=0 --name=ab --sync=1
#bw=41794KB/s, iops=10448

ok, so 30x faster.


I have read on the net some benchmark , and seem that the cacheflush is really slow on theses crucial


Now, same benchmark, but with stefan kernel patch + echo temporary write through 

crucial m550
------------
#fio --filename=/dev/sdb --direct=1 --rw=write --bs=4k --numjobs=2 --group_reporting --invalidate=0 --name=ab --sync=1
bw=177575KB/s, iops=44393 


:)

This sound like "zfs_nocacheflush" option in zfs. zfs recommand to enable it only with supercap ssds.



----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Jeudi 11 Septembre 2014 08:40:35 
Objet: RE: [pve-devel] ceph firefly in pve repos 

> # dd if=rand.file of=/dev/sdb bs=4k count=65536 oflag=dsync,direct 
> ^C17228+0 enregistrements lus 
> 17228+0 enregistrements écrits 
> 70565888 octets (71 MB) copiés, 70,4098 s, 1,0 MB/s 

That is about 250 IOPS?