I have a two-node RHEL5 cluster that runs the following Linux kernel and accompanying OCFS2 module packages:
* kernel-2.6.18-274.17.1.el5 * ocfs2-2.6.18-274.17.1.el5-1.4.7-1.el5 A 2.5TB LUN is presented to both nodes via DM-Multipath. I have carved out a single partition (using the entire LUN), and formatted it with OCFS2: # mkfs.ocfs2 -N 2 -L 'foofs' -T datafiles /dev/mapper/bams01p1 Finally, the filesystem is mounted to both nodes with the following options: # mount | grep bams01 /dev/mapper/bams01p1 on /foofs type ocfs2 (rw,_netdev,noatime,data=writeback,heartbeat=local) ---------- When a single node is writing arbitrary data (i.e. dd(1) with /dev/zero as input) to a large (say, 10 GB) file in /foofs, I see the expected performance of ~850 MB/sec. If both nodes are concurrently writing large files full of zeros to /foofs, performance drops way down to ~45 MB/s. I experimented with each node writing to /foofs/test01/ and /foofs/test02/ subdirectories, respectively, and found that performance increased slightly to a - still poor - 65 MB/s. ---------- I understand from searching past mailing list threads that the culprit is likely related to the negotiation of file locks, and waiting for data to be flushed to journal / disk. My two questions are: 1. Does this dramatic write performance slowdown sound reasonable and expected? 2. Are there any OCFS2-level steps I can take to improve this situation? Thanks - -- Erik Schwartz <schwartz.eri...@gmail.com> | GPG key 14F1139B _______________________________________________ Ocfs2-users mailing list Ocfs2-users@oss.oracle.com http://oss.oracle.com/mailman/listinfo/ocfs2-users
