>>>>> "Mark" == Mark Lord <kernel@xxxxxxxxxxxx> writes: Mark> On 11-01-27 10:40 AM, Justin Piszcz wrote: >> >> >> On Thu, 27 Jan 2011, Mark Lord wrote: Mark> .. >>> Can you recommend a good set of mkfs.xfs parameters to suit the characteristics >>> of this system? Eg. Only a few thousand active inodes, and nearly all files are >>> in the 600MB -> 20GB size range. The usage pattern it must handle is up to >>> six concurrent streaming writes at the same time as up to three streaming reads, >>> with no significant delays permitted on the reads. >>> >>> That's the kind of workload that I find XFS handles nicely, >>> and EXT4 has given me trouble with in the past. Mark> .. >> I did a load of benchmarks a long time ago testing every mkfs.xfs option there >> was, and I found that most of the time (if not all), the defaults were the best. Mark> .. Mark> I am concerned with fragmentation on the very special workload Mark> in this case. I'd really like the 20GB files, written over a Mark> 1-2 hour period, to consist of a very few very large extents, as Mark> much as possible. Mark> Rather than hundreds or thousands of "tiny" MB sized extents. I Mark> wonder what the best mkfs.xfs parameters might be to encourage Mark> that? Hmmm, should the application be pre-allocating the disk space then, so that the writes get into nice large extents automatically? Isn't this what the fallocate() system call is for? Doesn't MythTV use this? I don't use XFS, or MythTV, but I like keeping track of this stuff. John _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
