SAS controllers and Home Servers

cavemanoc · 20 Nov 2014 at 19:25

I'm looking at upgrading my WHS box and am getting tired of running out of sata ports (I've currently used all of the onboard ports and the extra ones that came with the sata add in card (pci-e) that I installed.

Am I correct in thinking that a SAS card would allow me to daisy chain as many drives as I like - if so will it play nice with WHS 2011 (if I can ever find a copy :mad:

) and what do I need in the way of cables / backplanes? Don't want to break the bank so I'm guessing a 2nd hand LSI / Dell perc card?

Any down sides - hardware conflicts / loss of speed / chance of corruption etc versus the standard setup?

Frozennova · 20 Nov 2014 at 21:51

I use a Dell SAS6/IR cross flashed with the LSI IT Firmware which turns it into a dumb hba and removes it's raid capability. Card was about £15 quid off eBay then a pair of Sff8484 to 4x sata cables we're about a tenner.

So far it's been used with esxi, freenas, debian and windows server 2008 r2 without issue

cavemanoc · 21 Nov 2014 at 00:33

Is the SAS6/IR the lower tier to the Perc 6i? I found a couple of the Perc cards (with battery) for around the £20 mark all in - would that be a better option than the SAS6? - From a brief read around it seems that the SAS6 does not have the onboard raid controllers that the perc has?

Frozennova · 21 Nov 2014 at 07:54

Yea, the SAS6/IR is a lower tier card and only supports RAID 0/1.

The only thing you'll have to be aware of is both card support a maximum of 2TB drives.

If you wanted larger drive support then the HP P410 is a good shout but slightly dearer

cavemanoc · 21 Nov 2014 at 15:03

Good shout - thanks for the warning - that would have caused a large crinkle!

The HPs look good - may well stump up for something like that soon - is the battery unit needed if you're not using the RAID capability - I never bothered with my old scsi drives and got away with it?

Frozennova · 21 Nov 2014 at 17:08

Battery is only needed if you are using RAID as power loss can cause data loss without.

Kei · 21 Nov 2014 at 18:03

A SAS card in itself won't allow for daisy chaining, for that, you need an expander. (like a chenbro CK series, an HP 36 port or an intel RES2SV240) I got an LSI 8888elp for free and use it with an intel expander which gives me a total of 24 ports. (I've opted to dual link the expander and stick with 20 ports) At present I'm using 7 ports with WD SE's in RAID 5 playing it dangerous using write back caching with no BBU. My hba is limited to 3GB/s and 2TB disks like the dell suggested above, but the expander is capable of 6GB/s /SAS2. (as are the chenbro expanders, don't think the HP is)

Even with the 3GB/s limit it manages to sustain a decent performance. (running opensuse 13.1)

cavemanoc · 22 Nov 2014 at 13:21

Thanks for that - I have missed a step then - I thought it was just a matter of picking up the 4-in-1 cables that go sas-sata and plugging them into the SAS / Perc card. So the expander is required in addition to the SAS card? To save me constantly coming back with the simple questions - anyone able to point me to a hardware explanation so I can bring myself up to speed before I decide wa I need going forward?

Kei · 22 Nov 2014 at 13:54

The expander would only be required if you want more disks than the normal cheap 4 or 8 port cards support. (I'm running 12 on an 8 port card) If 8 disks is sufficient, no expander would be needed with a suitable 8 port card and a pair of forward breakout cables. (Not reverse)