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Please help superboyac build a server (2013 edition).
superboyac:
I'm trying to figure out which HBA card I'm going to get to connect all these drives. From what I can understand, people are saying it is not a good idea to use sas expanders with sata drives with ZFS. SO that means I have to use non-sas cards. The one that is recommend from here is the IBM m1015. This was also the same card that someone here recommended to me, so maybe that's the way to go.
But what i don't get is that the m1015 seems to use sas expanders also. No? I don't understand.
superboyac:
Of course, the other option is to just get real deal SAS drives. It will cost me, though.
superboyac:
So if I go the SATA route (no SAS expanders), I need an HBA and some port multipliers. I don't know what HBA to get, but Addonics has some port multipliers:
Please help superboyac build a server (2013 edition).
So maybe the IBM m1015 plus these multipliers?
superboyac:
Regarding using SATA drives with SAS, here's some more input that is making me go round and round:
Most of what you've read about using SAS expanders with SATA drives is just plain old fashioned FUD - stuff posted by people repeating things they didn't really understand or stuff promulgated by one particular system vendor with an agenda.
There is no significant issue. There was a bug in Opensolaris-derived systems that got (incorrectly) blamed on the combination of SAS expander with SATA drives because systems in that configuration could be shown to exercise the bug - but it was clearly and unabiguously a bug in the OpenSolaris code and NOT a side-effect of using SAS expanders with SATA drives. The bug existed in general and all ZFS-based systems were actually at some risk from it whether they used SAS expanders or not. It was fixed in Solaris 11 and separately on other related branches (like OpenIndiana). All of the posted FUD derives from this. It was propagated in some self-serving posts by one systems vendor who either couldn't or didn't want to bother fixing the (well published) bug in their OpenSolaris-based branch.
But if it makes you uncomfortable using then then don't use them.
Besides, as apnar posted above, serving the typical SOHO max of 24 drives using 3 8-port HBAs is almost always cheaper and faster than 1 HBA + expander. But if you need to support more drives or if you don't have the PCIe lanes to spare for the extra HBAs then expanders work great too.
--- End quote ---
I really am trying not to have to go to SAS drives, because that would just cost me quite a bit (>$3000). I want to use the SATA drives I already have. If using SATA drives with SAS is not as big a deal as I'm reading about, maybe the best way to do it is:
--server motherboard (SuperMicro)
--IBM m1015 HBA card
--SAS expanders to SATA drives
superboyac:
Is there a difference between a SAS expander and a breakout cable?
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