Am Sonntag, 5. August 2012 schrieb Stan Hoeppner: > On 8/5/2012 6:03 AM, Martin Steigerwald wrote: > > Well the default was 16 AGs for volumes < 2 TiB AFAIR. And it has > > been reduced to 4 for as I remember exactly performance reasons. Too > > many AGs on a single device can incur too much parallelity. Thats at > > least is what I have understood back then. > > For striped md/RAID or LVM volumes mkfs.xfs will create 16 AGs by > default because it reads the configuration and finds a striped volume. > The theory here is that more AGs offers better performance in the > average case on a striped volume. > > With hardware RAID or a single drive, or any storage configuration for > which mkfs.xfs is unable to query the parameters, mkfs.xfs creates 4 > AGs by default. The 4 AG default has been with us for a very long > time. It was never reduced. That does not match my memory, but I´d have to look it up. Maybe next week. I am pretty sure mkfs.xfs on a single partition on a single harddisk upto 2 TiB used 16 AGs for quite some time and now uses 4 AGs since quite some time already. I think I have noted the exact xfsprogs version where it was changed in my training slides. -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
