Are there any reasonable choices for bigger (3+ shelf) direct-connectedWhat I’m using currently:
RAID10 arrays, or are hideously expensive SANs the only option? I've
checked out the latest Areca controllers, but the manual available on
their website states there's a limitation of 32 disks in an array...
Adaptec / Areca cards + Promise V-Trac J610S (for 3.5” drives, if total storage is your concern). Multiple cards if necessary and you want dual-path to each drive.
http://www.promise.com/product/product_detail_eng.asp?segment=undefined&product_id=190
http://www.promise.com/product/product_detail_eng.asp?segment=undefined&product_id=189
Using two of the former with two Adaptec cards (Software raid 0 on top of them) with great success.
There’s 2.5” drive ones too from other manufacturers ... The Promise one here scared me at first until I got confirmation from several experts actually using them in place of Dell MD1000 and HP SAS expander boxes because of higher device compatibility (Dells only works with PERC, etc) and reasonable cost.
You probably don’t want a single array with more than 32 drives anyway, its almost always better to start carving out chunks and using software raid 0 or 1 on top of that for various reasons. I wouldn’t put more than 16 drives in one array on any of these RAID cards, they’re just not optimized for really big arrays and tend to fade between 6 to 16 in one array, depending on the quality.
High quality SAS expander boxes compatible with good, non-proprietary RAID cards are not those from T1 vendors. The Promise above has a large compatibility list, since it uses ‘standard’ controller chips, etc. There are several others. See the Adaptec and Areca SAS expander compatibility lists. Dual redundant path to drives is nice.
You can do direct-attached storage to 100+ drives or more if you want. The price and manageability cost go up a lot if it gets too big however. Having global hot spare drives is critical. Not that the cost of using SAN’s and such is low... SAS expanders have made DAS with large arrays very accessible though.
Sun has some nice solutions here too, but like all T1 vendors the compatibility lists are smaller. Their RAID card they sell is an OEM’d Adaptec and performs nicely. The Sun 4150 with a direct-attached SAS storage makes a pretty good DB server. And yes, you can run Linux on it or Solaris or OpenSolaris or Windows or some BSD variants.
