Brady Chang wrote: > Hello All, > I have an issue with fragmentation on a particular device > thanks for any advice. > > -Brady > > I have a Dell r510 with 12 disks > 2xraid 5 (6 disks each) > raid group1: > 48 GB carved out for os mounted as / > remaining space 2.7 TB for xfs mounted as /data1 > raid group2: > 48 GB for swap > remaining space 2.7 TB for xfs mounted as /data2 > > The strange thing is that /data1 never gets fragmented where as /data2 > is badly fragmented. > I believe increase allocsize would help, but not sure how to explain why > /data2(/dev/sdd) always gets fragmented and not /data1(/dev/sdb) > > It's a data warehouse application. the I/O is balanced between /data1 > and /data2: > output of xfs_db > [root@sdw4 data1]# xfs_db -c frag -r /dev/sdb > actual 14353, ideal 13702, fragmentation factor 4.54% > [root@sdw4 data1]# xfs_db -c frag -r /dev/sdd > actual 408674, ideal 13719, fragmentation factor 96.64% so each file has 30 extents on average (actual/ideal) > df output > /dev/sdb 2.7T 967G 1.8T 36% /data1 > /dev/sdd 2.7T 1.1T 1.7T 39% /data2 1.1T/408674 extents is ~3M per extent, not so good. How many files are on each fs? > LABEL=/data1 /data1 xfs > allocsize=1048576,logbufs=8,noatime,nodiratime 0 0 > LABEL=/data2 /data2 xfs > allocsize=1048576,logbufs=8,noatime,nodiratime 0 0 Everything but the first option is default, BTW. Is xfs_info output on the 2 filesystems the same? Otherwise Emmanuel's idea is a good one, maybe it's not as balanced as you think it is, or maybe they have aged differently and have different amounts of freespace (see the freesp command in xfs_db) > By the way, the os is RHEL 5.5 kernel 2.6.18-194.11.1.el5 Was Red Hat support not helpful? -Eric _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
