William Warren wrote : > On 2/9/2011 4:47 AM, Matthias Saou wrote: > > Hi, > > > > I just got this isolated RHEL6 server, with hardware I've never used > > before. It's a Supermicro X8STi motherboard (Xeon i7 920) with two cheap > > SATA disks (WD10EADS-00P8B0) using software RAID-1. > > > > The system is unusable : A quick strace of various processes shows very > > long waits during many different I/O related calls such as open, read, > > pread, stat, fdatasync... > > > > I've tried failing every other partition in order to be sure to use only > > one disk for a while, with the same results. Running RAID rebuilds > > sometimes peaks at 60-100MB/s but very rarely. Right now for instance, > > the main 900GB RAID-1 is rebuilding from sda2 to sdb2 and it's > > reporting 400kB/s with system load of over 2 (the server is idle apart > > from this rebuild). While this is going on, even smartctl on sdb takes > > time to respond. When no rebuild is in progress, the problems are the > > same. > > > > I'm using the latest released 2.6.32-71.14.1.el6.x86_64 kernel, and > > here is the detail of the SATA controller(s) : > > > > 00:1f.2 IDE interface: Intel Corporation 82801JI (ICH10 Family) 4 port > > SATA IDE Controller #1 Subsystem: Super Micro Computer Inc Device 0009 > > Kernel driver in use: ata_piix > > Kernel modules: ata_generic, pata_acpi, ata_piix > > 00:1f.5 IDE interface: Intel Corporation 82801JI (ICH10 Family) 2 port > > SATA IDE Controller #2 Subsystem: Super Micro Computer Inc Device 0009 > > Kernel driver in use: ata_piix > > Kernel modules: ata_generic, pata_acpi, ata_piix > > > > No errors reported by the kernel apart from some processes stuck for > > more than 120s before the last reboot. Has anyone seen disk I/O issues > > like this with RHEL6 and similar hardware? > > > > Matthias > > > > PS: A possibly important detail is that this is a server provided by > > ovh.com which has been offering RHEL6 for a while but still has it > > marked as "BETA" (it's not the RHEL6 beta, it's how they consider their > > offering of RHEL6), which might indicate known problems between their > > typical hardware and RHEL6. I didn't find any clues with a quick > > bugzilla search... > > > are you using the bios raid or MD raid? If you are using biod raid you > are running everything effectively pio mode and it's going to suck. Put > the bios in ahci(not raid mode) and then use Linux raid from inside the > partitioning scheme(which is md raid) i bet performance will be much better.
I probably forgot to detail, but it's indeed MD RAID I'm using. No one in their right mind would use one of those cheap motherboard pseudo RAID, would they? :-) Anyway, I've reinstalled the server with RHEL5 and it's running fine now. Definitely something going on between this particular hardware and RHEL6.0... since I intend to use it only as a KVM hypervisor, and that RHEL6 still doesn't support the new cool stuff that would make a difference (like KSM), I'll stick with RHEL5, even though all of the virtual servers running under it will be RHEL6. Matthias -- Clean custom Red Hat Linux rpm packages : http://freshrpms.net/ Fedora release 14 (Laughlin) - Linux kernel 2.6.35.10-72.fc14.x86_64 Load : 0.07 0.07 0.08 _______________________________________________ rhelv6-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/rhelv6-list
