4 SAS Drives on Dell T7500 - What should I do?

meamsuperman

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Feb 4, 2014
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Long story short, I found a very inexpensive Dell Precision T7500 and have been playing around with it. I upgraded it to dual xeon W5580s (from dual 5520s). I just found 4 Seagate Cheetah 15k.5 SAS drives for $15. I didn't know SAS was a thing until after I bought them (I thought I could just use SATA cables).

I believe the Dell has an internal SAS controller but the inputs just look like regular SATA connectors. I also don't have any cables to connect to the SAS drives (I have plenty of SATA cables... and I'm tempted to "modify" them to make them fit on the SAS drive).

So, what should I do? Buying an SSD and tossing/selling the drives would be the easiest option, but I like a challenge. And I'm cheap. And I haven't been able to test to see if the drives even work yet.

Anyone have any experience with this sort of thing?
 
Naw you need a SAS controller. It has a built in RAID controller but not a SAS controller. Even though they are 15k drives honestly unless you did one big RAID 0, even then it wouldn't be as fast as a SSD but then again that also only has SATA 3.0Gb on it too but even then a SSD would probably be faster.

You can look into like a Dell SAS 5 iR HBA adapter which are pretty cheap on ebay or a Dell PERC 5/6 RAID card which all support SAS. You would need a SAS breakout Cable for that as well.
 


Interesting, and thank you for your reply. So even if it has "Four 7-pin SAS connectors" on the motherboard I would still need an SAS controller card? It says it has an LSI Logic SAS1068E IR something-or-other at startup. Does that mean anything (I googled it but the answers I found were sort of confusing)? I'm definitely not buying an SAS controller if there isn't one already on there. Definitely not worth the money/hassle.
 
Thanks! That seems like it will work and I'll give it a shot. Do you happen to know what would happen if I just cut the plastic side part off of the connector for a Sata power and data cable so one end of each would fit on the SAS drive? I'd rather do that to test the SAS drives before waiting for/spending money on actual cables.

From what I've seen it seems like SAS drives have the different connector to avoid connecting them to SATA inputs, so it seems like it might work unless the power connector is different.
 
Yes, you can use SAS drives. The Dell 690 uses the Dell SAS 5/iR Controller based on the LSI Logic SAS1068 I/O Controller. I've been running 4 x 147GB SAS drives as RAID0 in the Dell 690 for years. The Dell T7500 uses the Dell SAS 6/iR Controller which is also based on the LSI Logic SAS1068 I/O Controller but this uses the 'E' version of the LSI Controller. You can see the differences between the two versions here: http://www.dell.com/downloads/global/power/ps2q08-20080312-Dixit.pdf.

What you need to connect the SAS drives to your Dell's 4 x SAS ports is something called an 'Interposer Board' as shown here: http://www.amazon.com/Genuine-Dell-Interposer-SFF-8482-Convert/dp/B00E0OFHM8. Then you can use a standard SATA power and data cable to connect your drives.

I hope this helps.
 
I appreciate the answers given and have had some success with my SAS issue. Here's what I've learned for the Dell Precision T7500:

Interposer Board - I did not try this but that looks like it will do the trick. But the current price of $24.02 including shipping was way above my price range.

The "7 Pin SATA Serial ATA to SAS 29 Pin & 4 Pin Cable Male Connector Adapter F5" worked perfectly. I also used (and prefer) http://www.ebay.com/itm/271982829370?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT and that worked without any issues. Well, the drives got really hot, but they worked. And each cord was less than $4 including shipping.

The moral of the story is that I just went with an SSD in the end. Aside from being an interesting learning experience, it wasn't really worth the hassle.

I hope nobody else finds this useful because if you do you're in a crappy situation to begin with.

But thank you to mtahir and drtweak for helping out.
 
SAS drives are used mostly in servers and often run 24/7. That's why I use them for video - performance and reliability. You have to monitor them with hard drive monitoring software (along with the other drives). I've not had any failures unlike with other drives. The Dell690 and T7500 don't seem to be setup well for cooling in that area. On the Dell690 I run SpeedFan to keep things cool. Once it's all setup, it runs well.

I suppose your setup depends on what you're trying doing at the end of the day. I'm glad you found a solution.
 



Actually there is a spot for a fan. Think it is a 80mm that goes between the two sets of hard drives. If there is no fan there, there should at least be the plastic mount for it that pulls down to where the motherboard is FYI.

But yea Unless you really needed the RAID features a SSD is better unless the PERC card has a backup battery on it.
 
You're right, drtweak, there is a fan there but it I don't find it cools well enough. It seems to run at constant speed and SpeedFan can't access it, although, I'm not sure if it can go faster. Those far two hard drives do get hot, especially the one just under the PSU. I use a Dell PERC 6 with battery backup for RAID0 which is backed up externally. I think it might be best to leave the slot under the PSU free or run the fans faster when you need to (the big Card Fan is the best to cool the drives). Unfortunately, SpeedFan can't detect the drives when they're connected to the PERC, otherwise, you can setup a threshold and leave SpeedFan on auto.