Multiple disks on LSI MegaRAID cards
Okay so this is something I've been a bit confused about, and probably is an easy thing to clarify.
Take the LSI MegaRAID 9260-4i card like this one:
http://www.newegg.ca/Product/Product.aspx?Item=N82E16816118107
This card has a single SFF connector and is intended to connect to up to 4x disks.
However on LSI's website, under specifications:
http://www.lsi.com/products/storagecomponents/Pages/MegaRAIDSAS9260-4i.aspx
It says that it supports "Up to 128 SATA and/or SAS devices", and "64 logical drive support".
How is this possible? Are you supposed to just put multiple cards into a server? If so, do the cards automatically detect each other and handle it or is there special configuration needed?
Can you mix and match LSI cards of the same product line? E.g. can I put in 2x LSI MegaRAID 9260-4i cards and 1x LSI MegaRAID 9260-8i card, for a total of 16 disks?
Take the LSI MegaRAID 9260-4i card like this one:
http://www.newegg.ca/Product/Product.aspx?Item=N82E16816118107
This card has a single SFF connector and is intended to connect to up to 4x disks.
However on LSI's website, under specifications:
http://www.lsi.com/products/storagecomponents/Pages/MegaRAIDSAS9260-4i.aspx
It says that it supports "Up to 128 SATA and/or SAS devices", and "64 logical drive support".
How is this possible? Are you supposed to just put multiple cards into a server? If so, do the cards automatically detect each other and handle it or is there special configuration needed?
Can you mix and match LSI cards of the same product line? E.g. can I put in 2x LSI MegaRAID 9260-4i cards and 1x LSI MegaRAID 9260-8i card, for a total of 16 disks?
PowerEdgeTech
If you connect a multi-drop cable to one of the SAS connectors, then yes, only 4 drives are supported. However, if you connect that SAS connector to a SAS expander, then you can connect many more devices through that one connector. Most servers that support 12, 16, 24, etc. drives have a SAS expander built into the system/backplane in order to support that many drives. So, if you are building your own, you would need one of these devices to accommodate more drives. Problems in doing this in a system not designed for it include powering the drives and the simple matter of space. External enclosures are a common method of expanding the number of disks a controller can use.
ASKER
Hang on... really??
So say I have an big Chenbro 4U server case with 16 SATA hard disk bays and a big redundant power supply. It's suitable to store and power 16 disks. But it doesn't have a SAS expander I don't think, it just has 4x of the Mini-SAS internal connectors, one for each row of 4x disks.
So you're saying if I had a SAS expander in the server, e.g. ...
http://www.ebay.ca/itm/Intel-RAID-Expander-Card-RES2SV240-SAS-SATA-24-Port-Expander-Card-w-Cables-/151124397867?pt=US_Server_Disk_Controllers_RAID_Cards&hash=item232fb74f2b&_uhb=1
(just as an example, substitute for some other model compatible with LSI)
Then this server can happily run 16 disks on an LSI MegaRAID 8260-4i, instead of having to go and buy an LSI MegaRAID 8260-16i?
So say I have an big Chenbro 4U server case with 16 SATA hard disk bays and a big redundant power supply. It's suitable to store and power 16 disks. But it doesn't have a SAS expander I don't think, it just has 4x of the Mini-SAS internal connectors, one for each row of 4x disks.
So you're saying if I had a SAS expander in the server, e.g. ...
http://www.ebay.ca/itm/Intel-RAID-Expander-Card-RES2SV240-SAS-SATA-24-Port-Expander-Card-w-Cables-/151124397867?pt=US_Server_Disk_Controllers_RAID_Cards&hash=item232fb74f2b&_uhb=1
(just as an example, substitute for some other model compatible with LSI)
Then this server can happily run 16 disks on an LSI MegaRAID 8260-4i, instead of having to go and buy an LSI MegaRAID 8260-16i?
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ASKER
Upon closer inspection of my case, the SFF connectors were not what I was expecting (they were not the type that would typically plug into a RAID card). Indeed, there is a special SAS expander that is supported by Chenbro specifically for this purpose that was not included in my case.