> On Thu, Feb 01, 2007 at 08:34:20PM -0000, Pete Clarke wrote: >> Hi there, >> >> I have a file server, running Etch, with the following specs: >> >> P4, 1.7Ghz >> 512MB Ram >> 2 x SI based SATA I controllers >> 4 x Maxtor 250GB SATA drives >> >> It is set up with software RAID 5, and the overall performance is >> terrible. >> >> Every time it reboots (which happens due to dodgy power!), it does a >> RAID >> resync, this takes up 90% CPU time (for md0_resync process) for 50 >> hours!! >> During this time, ANY access to the drive is painful. >> >> Now, I expected software RAID 5 to be slow, but not this bad - this is >> the >> reading from hdparm: >> >> bungo:~# hdparm -tT /dev/md0 >> >> /dev/md0: >> Timing cached reads: 2 MB in 4.71 seconds = 435.05 kB/sec >> Timing buffered disk reads: 8 MB in 3.13 seconds = 2.56 MB/sec >> >> >> Bad eh? >> >> Becuase they're SATA drives, hdparm cannot tune them - or indeed read >> their >> current settings. Is there any way I can speed this beast up, if not I >> am >> going to go back to my old PPro200-based file server, running SCSI->FCAL >> bridge. >> > > Wow, that is awful. > > I dont' do raid5 since I only have two disks. > > Two identical Seagate Barracuda 7200 80 GB SATA drives (with the SATA I > rate limiting jumper removed), on my Asus MB nVidia chipset SATA-II > ports. Each drive has three partitions, to for raid1, one for LVM. > > hdparm -tT /dev/md0 > > /dev/md0 > Timing cached reads: 2424 MB in 2.00 seconds = 1212.23 MB/sec > Timing buffered disk reads: 62 MB in 0.84 seconds = 73.44 MB/sec. > > What happens if you time the raw drives instead of md0? For me on raid1, > its basically the same. I'm wondering if one or more of your drives are > in difficulty and its slowing down the whole array. > > What does smartmontools say about the drive's S.M.A.R.T.s? >
I get: bungo:~# smartctl --all /dev/sda smartctl version 5.36 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen Home page is http://smartmontools.sourceforge.net/ Device: ATA ST3250620AS Version: 3.AA Serial number: 9QE0MLDS Device type: disk Local Time is: Thu Feb 1 22:14:32 2007 GMT Device does not support SMART Error Counter logging not supported [GLTSD (Global Logging Target Save Disable) set. Enable Save with '-S on'] Device does not support Self Test logging As for individual drive performance : bungo:~# hdparm -tT /dev/sda /dev/sda: Timing cached reads: 322 MB in 2.00 seconds = 160.99 MB/sec Timing buffered disk reads: 106 MB in 3.00 seconds = 35.29 MB/sec bungo:~# hdparm -tT /dev/sdb /dev/sdb: Timing cached reads: 348 MB in 2.01 seconds = 173.30 MB/sec Timing buffered disk reads: 4 MB in 4.62 seconds = 886.44 kB/sec bungo:~# hdparm -tT /dev/sdc /dev/sdc: Timing cached reads: 320 MB in 2.00 seconds = 159.67 MB/sec Timing buffered disk reads: 36 MB in 5.39 seconds = 6.67 MB/sec bungo:~# hdparm -tT /dev/sdd /dev/sdd: Timing cached reads: 342 MB in 2.01 seconds = 170.41 MB/sec Timing buffered disk reads: 4 MB in 4.29 seconds = 954.93 kB/sec Rather poo ... I *must* be doing something wrong .. I can't believe SATA performance is *THIS BAD*... Cheers, Pete. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
