> -----Original Message-----
> From: xfs-bounce@xxxxxxxxxxx [mailto:xfs-bounce@xxxxxxxxxxx] On Behalf
> Nathan Scott
> Sent: Wednesday, June 07, 2006 5:43 PM
> To: Jan Wagner
> Cc: xfs@xxxxxxxxxxx
> Subject: Re: separate log and structure from user data device?
[ ... ]
> > I'm getting only about 500mbits/s write speed into the file
> > writing 1024 byte or much larger chunks) with the above code on XFS
> > the rtdev on a RAID0 /dev/md0 and "actual" XFS on /dev/hda6. With
> > directly on /dev/md0 and no realtime section but logdev=/dev/hda6,
> > throughput is a nice ~2.5gbits/s.
> Sounds like youre comparing buffered to direct IO? (and for a very
> small amount of data that goes straight to the page cache for your
> buffered writes, and you're not accounting flush times). But thats
> just a guess, maybe your md0 really does do 2.5gbits/s? Doubt it.
I just wanted to comment that this is about 320 MB/s which is very
reasonable for a 6 disk raid0 volume (between 50 and 60 MB/s per drive
with 6 disks). It would be kind of at the edge for a hardware raid 5
(but I know that 3ware yields ~315MB/s sequential writes with RAID5
Anyway -- just a note.