Messages in this thread | | | Date | Tue, 23 Jun 1998 22:46:04 -0500 (EST) | From | Chris Atenasio <> | Subject | Re: striping (RAID0) performance ? |
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On Tue, 23 Jun 1998, Davide Rossetti wrote:
> so, you see a major inprovement in disk seek overlapping, don't you ?
Definately! Then again I use 8k chunks...
Personalities : [1 linear] [2 raid0] [3 raid1] [4 raid5] read_ahead 128 sectors md0 : active raid0 sda1 sdb1 4192896 blocks 8k chunks
/dev/sda: Timing buffered disk reads: 32 MB in 4.86 seconds = 6.58 MB/sec
/dev/sdb: Timing buffered disk reads: 32 MB in 4.85 seconds = 6.60 MB/sec
/dev/md0: Timing buffered disk reads: 32 MB in 2.95 seconds =10.85 MB/sec
Attached devices: Host: scsi0 Channel: 00 Id: 00 Lun: 00 Vendor: SEAGATE Model: ST32550W Rev: 8104 Type: Direct-Access ANSI SCSI revision: 02 Host: scsi0 Channel: 00 Id: 01 Lun: 00 Vendor: SEAGATE Model: ST32550W Rev: 8104 Type: Direct-Access ANSI SCSI revision: 02
> In real life those are not zeroes. they are data from/to our supercomputer > memories. And in our QCD(Quantum Cromo Dynamics) simulations, there are > HUGE amount of data to be read/written.
Sounds like fun! You might be better off with chunk size < buffer size. (just a pseudorandom guess really) Then again is fs even threaded in 2.0?(can any fs guru verify this) I'm on 2.1.106ac3 using a 2940w which seems concrete even with SMP+RAID+realtek 8029<g>.
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