On May 17, 2012, at 12:19 PM, Paynter, Richard wrote:
> I have a customer who wants to set zfs_arc_max to 1G for a 16G system, and 2G
> for a 32G system. Both of these are SAP and/or Oracle db servers. They
> apparently want to maximize the amount of memory available for the
This is the best use case of the zfs_arc_max tunable.
> My question, now, is whether it would be advisable to do this, and – if not –
> what the impact might be.
For this use case, it is a good idea. The impact of not setting it occurs when
want to start a memory-hogging program, the request for arc to shrink can take
while to satisfy, and the memory-hog might not be designed to cope with
memory allocation requests.
> The 32G system is an M3000; the 16G system is a V490. Both are running
> Solaris 10 Update 8, patched to 147440-09.
> I have a feeling that setting zfs_arc_max this low is not a good idea, but
> would like to get some corroborating information/references, if possible.
This use case is why the zfs_arc_max tunable exists.
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