I have 159x 15K RPM SAS drives I want to build a ZFS appliance with. 75x 145G 60x 300G 24x 600G The box has 4 CPUs, 256G of RAM, 14x 100G SLC SSDs for the cache and a mirrored pair of 4G DDRDrive X1s for the SLOG. My plan is to mirror all these drives and keep some hot spares. My question is: should I create three pools (one for each size of drives) and share the cache and slog among them or should I create a single pool with them all? I''m thinking of creating a single pool to get maximum IOPS early on, even tho I understand that once I''ll have filled the 145G drives I''ll end up having smaller stripes and less performances. Would you do the same? Is there any reason not to do that? Thanks Ian -- This message posted from opensolaris.org
Another question: all those disks are on Dell MD1000 JBODs (11 of them) and we have 12 SAS ports on three LSI 9200-16e HBAs. Is there any point connecting each JBOD on a separate port or is it ok cascading them in groups of three? Is there a bandwidth limit we''ll be hitting doing that? Thanks -- This message posted from opensolaris.org
On Sat, Dec 18, 2010 at 7:26 AM, Ian D <reward72 at hotmail.com> wrote:> Another question: all those disks are on Dell MD1000 JBODs (11 of them) > and we have 12 SAS ports on three LSI 9200-16e HBAs. Is there any point > connecting each JBOD on a separate port or is it ok cascading them in groups > of three? Is there a bandwidth limit we''ll be hitting doing that? > > Thanks > >It''s fine to cascade them. SAS is all point-to-point. I strongly doubt you''ll hit a bandwidth constraint on the backend, especially if you have the shelves multipathed, but if that''s a concern you will get more peak bandwidth putting them on separate ports. --Tim -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20101218/3ba37c75/attachment.html>
On 12/18/10 10:49 AM, Ian D wrote:> I have 159x 15K RPM SAS drives I want to build a ZFS appliance with. > > 75x 145G > 60x 300G > 24x 600G > > The box has 4 CPUs, 256G of RAM, 14x 100G SLC SSDs for the cache and a mirrored pair of 4G DDRDrive X1s for the SLOG. > > My plan is to mirror all these drives and keep some hot spares. > > My question is: should I create three pools (one for each size of drives) and share the cache and slog among them or should I create a single pool with them all? >The answer really depends on what you want to do with pool(s). You''ll have to provide more information. -- Ian.
> The answer really depends on what you want to do with > pool(s). You''ll > have to provide more information.Get the maximum of very random IOPS I get can out of those drives for database usage. -- This message posted from opensolaris.org
On Sat, Dec 18, 2010 at 4:24 PM, Ian D <reward72 at hotmail.com> wrote:> > The answer really depends on what you want to do with > > pool(s). You''ll > > have to provide more information. > > Get the maximum of very random IOPS I get can out of those drives for > database usage. > -- > >Random IOPS won''t max out the SAS link. You''ll be fine stacking them. But again, if you have the ports available, and already have the cables, it won''t hurt anything to use them. --Tim -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.opensolaris.org/pipermail/zfs-discuss/attachments/20101218/9dbff870/attachment.html>