Lars Schimmer wrote: > Justin Piszcz wrote: > > > On Wed, 18 Jul 2007, Rui Santos wrote: > > >> Hi, > >> > >> I'm getting a strange slow performance behavior on a recently installed > >> Server. Here are the details: > >> > >> Server: Asus AS-TS500-E4A > >> Board: Asus DSBV-D ( > >> > http://uk.asus.com/products.aspx?l1=9&l2=39&l3=299&l4=0&model=1210&modelmenu=2 > >> > >> ) > >> Hard Drives: 3x Seagate ST3400620AS ( > >> > http://www.seagate.com/ww/v/index.jsp?vgnextoid=8eff99f4fa74c010VgnVCM100000dd04090aRCRD&locale=en-US > >> > >> ) > >> I'm using the AHCI driver, although with ata_piix, the behavior is the > >> same. Here's some info about the AHCI controler: > >> > > With three disks, if everything was perfect yeah 120MB/s writes. When I > > had started out with 4 raptors I was getting 164MB/s read and write. By > > default with no optimizations you will not get good speed. > > > With no optimizations with 10 raptors I get 180-200MB/s, with > > optimizations, 464MB/s write and 622MB/s read. > > > 1. Use XFS if you wan't speed. > > 2. Use 128k, 256k or 1MiB chunk size. > > 3. Use 8192k, 16384k stripe_cache_size. > > 4. Use 65536 readahead size. > > > These are only some of the optimizations I use. > > One question in between, which option of these I can set after RAID5 is > filled with data? > E.G. I setup a 9 disk SOFT-RAID5 with XFS and 3125669888 blocks level 5, > 128k chunk, algorithm 2 [9/9] [UUUUUUUUU]. > Speed is not really fast, I assume it could be faster. You can chage values from 3) and 4) on the fly by echoing values to: 3) /sys/block/md?/md/stripe_cache_size 4) /sys/block/<harddrive>/queue/read_ahead_kb About option 2) I don't how to reconfigure that. I used the following: tar make new raid with correct option untar > > > > Justin. Rui > > > MfG, > Lars Schimmer - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
