On Wed, Feb 08, 2006 at 10:35:32AM -0500, Joey Hess wrote: > Package: partman-ext3 > Severity: important > > ----- Forwarded message from Leo Bogert <[EMAIL PROTECTED]> ----- > > From: Leo Bogert <[EMAIL PROTECTED]> > Date: Wed, 8 Feb 2006 08:02:30 +0100 > To: [email protected] > Subject: (Severe?) Performance issues with ext3 created on RAID5 with partman > X-Mailer: Microsoft Office Outlook, Build 11.0.6353 > > Hello, > > I recently installed the following system: > Celeron 2800 MHz 64 bit, running on an ICH7 board. > 2 GB RAM > [3x 300GB SATA] <=> [sofware RAID5] <=> [loop-AES encryption] <=> [ext3fs] > running on Debian-amd64 testing, kernel 2.6.15.2 > > I created the RAID5 and ext3fs using the Debian installer. > Now my problem is: The read speed from the harddisks does not go over > exactly 51 MB/s. (mesured several times with different files by dd > if=/some-large-file of=/dev/zero) > When doing dd if=/dev/md1 of=/zev/zero I get almost exactly 100 MB/s though, > I also tried that with different offsets. > So the read speed of the RAID5 without any overhead added is 100 MB/s. > Now of course, one would first assume that the encryption is the bottleneck > because it uses much CPU power. > But I used /dev/shm to benchmark loop-AES also and it was at 270 MB/s.
50M/s on one drive. 3 disk raid5 is 2 data + 1 parity setup, so read should be 2 * 50M/s = 100M/s. Looks sane to me. What speed was it expected to run at? Certainly not 150M/s since that would be the read speed including the parity data. I see no indication of any bottlenecks. I am actually impressed it runs that efficiently. Len Sorensen -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
