Top-posting myself, I changed the motherboard BIOS (from IDE to AHCI) and initrd (adding ahci.ko), and the output of lspci makes a bit more sense: SATA controller [0106]: Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) 6 port SATA AHCI Controller [8086:2922] (rev 02) Kernel driver in use: ahci Kernel modules: ahci However, now the rebuild is even slower, at ~12MB/sec. A disk on the ICH9R onboard controller (ahci): # hdparm -tT /dev/sdd /dev/sdd: Timing cached reads: 8030 MB in 2.00 seconds = 4022.76 MB/sec Timing buffered disk reads: 166 MB in 3.02 seconds = 54.98 MB/sec A disk on the PCI-X (sata_mv) controller: # hdparm -tT /dev/sda /dev/sda: Timing cached reads: 8094 MB in 2.00 seconds = 4054.45 MB/sec Timing buffered disk reads: 324 MB in 3.01 seconds = 107.73 MB/sec Googling reveals other people with slow AHCI disks on new (> 2.6.23) kernels. Would someone using disks on an AHCI controller and a new kernel please send me timed reads? This doesn't feel like a linux-raid issue anymore, perhaps I should take this to the lkml? Perhaps I've missed something else in the BIOS.. Thanks, Richard On Mon, Sep 08, 2008 at 01:50:21PM -0400, Richard Michael wrote: > On kernel 2.6.26.3 with mdadm 2.6.7, I'm building two RAID5 arrays of > three drives each from six Seagate 1TB drives (ST31000340NS) on two > different controllers. > > Initial creation is rather slow for the array of disks on onboard > controller, about ~17MB/sec. The creation of the array on the PCI-X > controller was much faster, about ~90MB/sec. (Note: the creation is > sequential, I'm not creating these two arrays simultaneously.) > > Three drives on one array are connected to the onboard SATA controller of > an Asus P5EWS Pro motherboard. lspci shows me two IDE interfaces, one > four port and the other two port which I suppose correspond, in total, > to the six onboard ports: > > Intel Corporation 82801IR/IO/IH (ICH9R/DO/DH) > 4 port SATA IDE Controller (rev 02) > Intel Corporation 82801I (ICH9 Family) > 2 port SATA IDE Controller (rev 02) > > They both use the ata_piix kernel module. > > > The other controller is an eight port SuperMicro PCI-X controller, > AOC-SAT2-MV8, which has been mentioned on the list in the past: > > Marvell Technology Group Ltd. 88SE6145 SATA II PCI-E controller (rev a1) > > It uses the sata_mv kernel module. > > > I've created both RAID5 arrays with default parameters, using simply: > mdadm --create /dev/md2 --raid-devices=3 --level=raid5 > /dev/sdd2 /dev/sde2 /dev/sdf2 > > > hdparm shows me all drives are using udma6 (e.g. "hdparm -i /dev/sda"), > so I don't think it's a DMA issue (anyway, I've read all SATA drives use > DMA.. ?). > > It seems like a controller issue. Perhaps a different driver is > available for the onboard Intel controller; or some tunables in libata? > > Any suggestions? > > Thanks, > Richard > -- > 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 -- 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
