On Mittwoch, 23. Juni 2010 Andi Kleen wrote: > I don't know if it's the only reason, but XFS does a lot of data > structure locking and updates per allocation group, so spreading > to multiple AGs gives better scalability to many CPUs. This only helps if there are metadata operations, right? So in the case where you have one big database "file" of 50GB, it should be ordered sector-by-sector to get the maximum performance, and minimize disk-head movement. And I don't believe XFS would scatter a single big file around several AGs, as far as I know even all files within the same dir are grouped within a single AG. The AG "scattering" is done for separate dirs only. > Also I suppose it's good to avoid hot spots on the underlying > device. A database file is staying on the same place "forever" and will be overwritten all the time, so it doesn't matter for the "hot spot" case. -- mit freundlichen Grüssen, Michael Monnerie, Ing. BSc it-management Internet Services http://proteger.at [gesprochen: Prot-e-schee] Tel: 0660 / 415 65 31 // Wir haben im Moment zwei Häuser zu verkaufen: // http://zmi.at/langegg/ // http://zmi.at/haus2009/
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