RAID Card Help

[Guest]

Hi, for my personal rig I'm planning on having 3 operating systems, 1 mac, 1 linux, and 1 windows each starting off with 2 SSDs (RAID 0) for a total of 6 and possibly upgradable later to a maximum of 4 SSDs for each OS making the max grand total of 12, so for this setup, I'm not sure how many RAID cards I should get, don't get me wrong software RAID is nice and all but I need more room for SATA ports, so how many RAID cards should I get/have for this? 

[scottyseng]

Well, I think first you have to really consider if you want raid. It may be better just to get larger sized SSD from the start for each OS. Also keep in mind that a hardware RAID card does add to the boot time of the PC. It goes: Motherboard BIOS -> RAID card BIOS -> RAID card BIOS initializes all drives -> back to motherboard BIOS -> Windows (Or whatever OS you have set). My RAID card adds about 1 min to the boot time of my PC, pretty much negating any speed boost from the SSDs in RAID (At least for boot time).

 

I come from the LSI side of RAID cards since I own a LSI MegaRAID 9260-8i CV. For LSI, you have to keep in mind that you cannot expand RAID 0, 1, or 10. Only 5 or 6 are expandable. So if you want to add more SSDs to an existing array, you do have to delete the existing array and rebuild a new one. This means you will lose all data on the existing array and you will have to reinstall all of the operating systems. Also, to install to a RAID array (At least for LSI), you do have to load the driver for the RAID card in the Windows installer otherwise it will not pick up an of your raid drives.

 

Also, RAID cards list SAS ports as multiples of 4 because one SAS port can break out to 4  SATA/SAS devices using a cable. So a LSI MegaRAID 9340-4i (4i = 4 internal) = One SAS port onboard. A LSI MegaRAID 9361-8i (8i = 8 ports internal) = Two SAS ports onboard. If you see -4e or -8e, those denote external ports for LSI cards, which you should avoid unless you are using the card to connect to a separate server chassis (I assume you want all of the drives inside of your current PC).

 

You have two ways to go on the RAID card (Keep in mind one SAS port and be broken into 4 SATA / SAS ports):

 

First option is to get a 4 Port SAS RAID card, which are really expensive, but will natively support 16 drives. But it's so expensive for this (Not to mention I don't think there is a 93xx gen LSI RAID card with 4 internal ports) that you're better off with the second option.

 

The second and better option is to get a 2 port SAS RAID card, and buy a SAS expander. You take the two SAS ports from the RAID card and then plug them into the SAS expander. That expander will then give you more SAS ports to plug into (How many ports it gives you depends on how large the expander is, and of course, the larger the expander, the more it costs).

 

I would recommend a 93xx gen LSI RAID card since they have a faster 12 Gb/s bandwidth as opposed to my 92xx gen LSI MegaRAID 9260-8i CV.

 

A LSI MegaRAID 9361-8i would be a solid base for you (Keep in mind this is just the card, and the battery back up unit will have to be bought separately). You will then need a 12Gb/s SAS expander such as a Intel RAID Expander RES3CV360 36 Port SAS/SATA.

 

If you want a slightly cheaper option, you can look at the 92xx gen MegaRAID cards such as a 9260-8i with a 6Gb/s SAS expander such as a Intel RES2CV360 RAID Expander.

 

The cheapest method is to try your luck at ebay and find used raid controllers. You might be lucky and find some with battery back up units included. This is also the sketchiest method though.

 

You can also just buy a two port RAID controller and use that for up to 8 eight drives, then buy a SAS expander later down the road when you get more SSDs if you want to space out your investment.

 

I also would recommend getting the appropriate battery back-up system for your RAID card (For LSI, this would be the CacheVault). This makes sure in the case of power loss or system lock up, when you suddenly shut off your PC, you don't lose the data that's cached in the controller's DRR3 cache. If you lose that data, it is gone. One option around is to write through to the drives, but it hurts performance a bit since you're not using the DDR3 cache to the full potential.

 

I also recommend getting a battery back up unit for your PC plugged into a separate surge protector. This helps to be a back up in case your RAID card battery back up fails.

 

In the end, a good RAID card configuration for the drives will cost a fair bit of money (My RAID card was originally $780...I got it half off somehow in a Newegg sale). Keep in mind SAS to 4 SATA device cables are $25 each, so that also adds to the cost of the system.

 

There is a point of diminishing returns too, where adding more SSD drives won't give you as much of a boost as you'd hoped for each drive you add. You might consider Intel's NVMe SSD drive or Samsung's NVMe SSD drive.

[Guest]

Well, I think first you have to really consider if you want raid. It may be better just to get larger sized SSD from the start for each OS. Also keep in mind that a hardware RAID card does add to the boot time of the PC. It goes: Motherboard BIOS -> RAID card BIOS -> RAID card BIOS initializes all drives -> back to motherboard BIOS -> Windows (Or whatever OS you have set). My RAID card adds about 1 min to the boot time of my PC, pretty much negating any speed boost from the SSDs in RAID (At least for boot time).

 

I come from the LSI side of RAID cards since I own a LSI MegaRAID 9260-8i CV. For LSI, you have to keep in mind that you cannot expand RAID 0, 1, or 10. Only 5 or 6 are expandable. So if you want to add more SSDs to an existing array, you do have to delete the existing array and rebuild a new one. This means you will lose all data on the existing array and you will have to reinstall all of the operating systems. Also, to install to a RAID array (At least for LSI), you do have to load the driver for the RAID card in the Windows installer otherwise it will not pick up an of your raid drives.

 

Also, RAID cards list SAS ports as multiples of 4 because one SAS port can break out to 4  SATA/SAS devices using a cable. So a LSI MegaRAID 9340-4i (4i = 4 internal) = One SAS port onboard. A LSI MegaRAID 9361-8i (8i = 8 ports internal) = Two SAS ports onboard. If you see -4e or -8e, those denote external ports for LSI cards, which you should avoid unless you are using the card to connect to a separate server chassis (I assume you want all of the drives inside of your current PC).

 

You have two ways to go on the RAID card (Keep in mind one SAS port and be broken into 4 SATA / SAS ports):

 

First option is to get a 4 Port SAS RAID card, which are really expensive, but will natively support 16 drives. But it's so expensive for this (Not to mention I don't think there is a 93xx gen LSI RAID card with 4 internal ports) that you're better off with the second option.

 

The second and better option is to get a 2 port SAS RAID card, and buy a SAS expander. You take the two SAS ports from the RAID card and then plug them into the SAS expander. That expander will then give you more SAS ports to plug into (How many ports it gives you depends on how large the expander is, and of course, the larger the expander, the more it costs).

 

I would recommend a 93xx gen LSI RAID card since they have a faster 12 Gb/s bandwidth as opposed to my 92xx gen LSI MegaRAID 9260-8i CV.

 

A LSI MegaRAID 9361-8i would be a solid base for you (Keep in mind this is just the card, and the battery back up unit will have to be bought separately). You will then need a 12Gb/s SAS expander such as a Intel RAID Expander RES3CV360 36 Port SAS/SATA.

 

If you want a slightly cheaper option, you can look at the 92xx gen MegaRAID cards such as a 9260-8i with a 6Gb/s SAS expander such as a Intel RES2CV360 RAID Expander.

 

The cheapest method is to try your luck at ebay and find used raid controllers. You might be lucky and find some with battery back up units included. This is also the sketchiest method though.

 

You can also just buy a two port RAID controller and use that for up to 8 eight drives, then buy a SAS expander later down the road when you get more SSDs if you want to space out your investment.

 

I also would recommend getting the appropriate battery back-up system for your RAID card (For LSI, this would be the CacheVault). This makes sure in the case of power loss or system lock up, when you suddenly shut off your PC, you don't lose the data that's cached in the controller's DRR3 cache. If you lose that data, it is gone. One option around is to write through to the drives, but it hurts performance a bit since you're not using the DDR3 cache to the full potential.

 

I also recommend getting a battery back up unit for your PC plugged into a separate surge protector. This helps to be a back up in case your RAID card battery back up fails.

 

In the end, a good RAID card configuration for the drives will cost a fair bit of money (My RAID card was originally $780...I got it half off somehow in a Newegg sale). Keep in mind SAS to 4 SATA device cables are $25 each, so that also adds to the cost of the system.

 

There is a point of diminishing returns too, where adding more SSD drives won't give you as much of a boost as you'd hoped for each drive you add. You might consider Intel's NVMe SSD drive or Samsung's NVMe SSD drive.

okay let's say I just want to do a software RAID, how can I make room for more SATA ports? 

[scottyseng]

You probably can make do with a PCI Express SATA 3 port card like the HighPoint Rocket 640L. I don't know much about software RAID though.