also sprach Juri Haberland <juri@koschikode.com> [2003.08.21.1034 +0200]: > The first thing I notice is that you compare two different > filesystems: reiserfs and ext3. It is a known fact that reiserfs > is in most workloads *much* faster than ext3. Right, but while I had zero dataloss on ext3 filesystems so far, I have been screwed over by reiserfs a couple of times. What may be interesting to note is that `hdparm -T` reports about 370Mb/s on the RAID, but only about 260Mb/s on the non-RAID system. > How are your three (four) disks connected? Do they all have > a seperate IDE channel or do some of them share one? The disk on the fast machine is master to a slave disk. The first disk in the RAID is (unfortunately) master to a slave CD-ROM, which is, however, unused. > Do all disks have DMA turned on? This might be the problem. I turn DMA on, always, in /etc/inittab. But it doesn't work. Check this: ailab:~# hdparm -d1 /dev/hda /dev/hda: setting using_dma to 1 (on) HDIO_SET_DMA failed: Operation not permitted using_dma = 0 (off) So what's going on here??? > Try with the defaults values for chunk size, algorithm and ext3 stride. Which are? I could not see any. > Use an external journal for ext3 that is located on a RAID1. Does this really increase performance if the RAID1 would be on the same disk(s)? I note that RAID1 give absolutely no speed improvement on writes. RAID5 does a little. And journals are more written than read, no? -- Please do not CC me when replying to lists; I read them! .''`. martin f. krafft <madduck@debian.org> : :' : proud Debian developer, admin, and user `. `'` `- Debian - when you have better things to do than fixing a system Invalid/expired PGP subkeys? Use subkeys.pgp.net as keyserver!
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