Re: mkfs options for a 16x hw raid5 and xfs (mostly large files)

[Ralf Gross <Ralf-Lists@ralfgross.de>]

Justin Piszcz schrieb:
> >>I find that to be the case with SW RAID (defaults are best)
> >>
> >>Although with 16 drives(?) that is awfully slow.
> >>
> >>I have 6 SATA's I get 160-180 MiB/s raid5 and 250-280 MiB/s raid 0 (sw
> >>raid).
> >>
> >>With 10 raptors I get ~450 MiB/s write and ~550-600 MiB/s read, again
> >>XFS+SW raid.
> >
> >Hm, with the different HW-RAIDs I've used so far (easyRAID,
> >Infortrend, internal Areca controller), I always got 160-200 MiB/s
> >read/write with 7-15 disks. That's one reason why I asked if there are
> >some xfs options I could use for better performance. But I guess fs
> >options won't boost performance that much.
> 
> What do you get when (reading) from the raw device?
> 
> dd if=/dev/sda bs=1M count=10240

The server has 16 GB RAM, so I tried it with 20 GB of data.

dd if=/dev/sdd of=/dev/null bs=1M count=20480
20480+0 Datensätze ein
20480+0 Datensätze aus
21474836480 Bytes (21 GB) kopiert, 95,3738 Sekunden, 225 MB/s

and a second try:

dd if=/dev/sdd of=/dev/null bs=1M count=20480
20480+0 Datensätze ein
20480+0 Datensätze aus
21474836480 Bytes (21 GB) kopiert, 123,78 Sekunden, 173 MB/s

I'm taoo tired to interprete these numbers at the moment, I'll do some
more testing tomorrow.

Good night,
Ralf