On 6/27/2011 10:27 AM, Paul Anderson wrote: > There is nothing in the man page I see indicating what is good or bad > regarding allocation groups - either document it there or warn in the > software. If allocation algorithms are linear with respect to > allocation groups, the something like this should be stated in the man > pages. It is. From the 2nd paragraph of 'man 5 xfs': ...The data section is divided into a number of allocation groups. The number and size of the allocation groups are chosen by mkfs.xfs(8) so that there is normally a small number of equal-sized groups. The number of allocation groups controls the amount of parallelism available in file and block allocation. It should be increased from the default if there is sufficient memory and a lot of allocation activity. The number of allocation groups should not be set very high, since this can cause large amounts of CPU time to be used by the filesystem, especially when the filesystem is nearly full. More allocation groups are added (of the original size) when xfs_growfs(8) is run. Maybe some of this information could/should be moved to the agcount section of 'man mkfs.xfs'. I'll concede that "should not be set very high" is subjective for novice XFS users. To Marcus 20,000 may not be "very high". :) -- Stan _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
