Hi All,
I have stumbled across (via Google) a post on this mailing list in relation to performance issues with OCFS2. A little overview of our setup: 3 x Dell Poweredge R200 servers, w/8GB RAM, Dual Gig NIC's running VSphere 4.1 (ESXi w/Enterprise License) 1 x Dell Poweredge MD3000i ISCSI SAN w/15x 1tb SATA drives in RAID6 Each ESXi server runs 2 Gentoo Virtual machines running kernel 2.6.34 with ocfs2-tools - workload consists of lighttpd, Apache & Squid, with caching from the SAN to the local vm disks & RAM. Our problem lies within performance of the OCFS2 volume (which is ~10TB) over the disks. The iowait is constantly high (30-40% per server), and even though there are plenty of inodes and physical disk free, we cannot explain the problem. dnetwww2 ~ # df -h Filesystem Size Used Avail Use% Mounted on rootfs 18G 6.5G 11G 39% / /dev/sda3 18G 6.5G 11G 39% / rc-svcdir 1.0M 72K 952K 8% /lib64/rc/init.d udev 10M 184K 9.9M 2% /dev shm 2.0G 0 2.0G 0% /dev/shm /dev/sdb1 247G 29G 206G 13% /cache /dev/ram0 190M 13M 177M 7% /home/core /dev/ram1 190M 60M 130M 32% /home/moddb /dev/ram2 190M 20M 170M 11% /home/desura /dev/mapper/360024e8000758ab1000007624c1525dc1 9.8T 2.1T 7.7T 22% /home/shared dnetwww2 ~ # cat /etc/fstab --snip-- /dev/mapper/360024e8000758ab1000007624c1525dc1 /home/shared ocfs2 commit=15,heartbeat=local,data=writeback,noatime,user_xattr 1 2 dnetwww2 ~ # multipath -ll 360024e8000758ab1000007624c1525dcdm-0 , [size=9.7T][features=1 queue_if_no_path][hwhandler=0] \_ round-robin 0 [prio=6][active] \_ #:#:#:# sdc 8:32 [active][ready] \_ #:#:#:# sde 8:64 [active][ready] \_ round-robin 0 [prio=0][enabled] \_ #:#:#:# sdd 8:48 [active][ghost] \_ #:#:#:# sdf 8:80 [active][ghost] Now if I mount an ext4 formatted lun/partition from the MD3000i (mapped via iscsi&multipath-tools) I can read/write to it at 125MB/s with no issues. The ocfs2 mounted volume struggles to sustain 25-30MB/s read/write. :-( We have spent countless hours working (troubleshooting/debugging) this now without result. We've even replaced both controllers, switches, network cards and so on in an attempt to rule out a specific hardware cause, but it seems to be ocfs2 related. I've noted there are a number of new ocfs2 patches in Linux 2.6.35 & the yet to be released 2.6.36 - would like to know if any of these resolve this issue before we are forced to ditch ocfs2 and go back to NFS. Cheers, Greg
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