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So we're testing the SAS drives at work

I

imported_Phil

Diamond Member
We have four Fujitsu SAS 147Gb 10krpm drives and an LSI SAS 4-port controller in for testing at work at the moment, would you guys like to see some benchmarks?

If so, what?

We've had incredible difficulties running all four drives in RAID-0 (controller supports RAID 0 and 1 only) as it keeps dropping one of the drives at random.

However, HDTach reports a seek time of 5ms (you'll need to subtract rotational latency from that figure to get the real seek time) and a starting transfer rate of 95MB/sec. 😀

Thoughts?

(I should mention that this is running on a quad Xeon 1.9Ghz system with 2Gb of RAM. While I might be able to squeeze in audio/visual tests, bear in mind that I don't know if I'm in the office from one day to the next.)
 
Make sure your power supply is adequate. Had the same issue with one of my drives just dropping out like it was all of a sudden turned off--ended up being the PSU. So I added another one. Works just fine now.

HD Tach 3 them, and include screen shots / saved files. 🙂
Tas.
 
Originally posted by: tasburrfoot78362
Make sure your power supply is adequate. Had the same issue with one of my drives just dropping out like it was all of a sudden turned off--ended up being the PSU. So I added another one. Works just fine now.

HD Tach 3 them, and include screen shots / saved files. 🙂
Tas.
Click to expand...

Dual 520W redundant units 😉
 
Oh yeah, the other nice fact is that with a different cable (which, BTW, is a straaange connector; kinda like SATA connectors but different) you can use it with regular SATA drives. I'll try and post a pic of the cable, which splits the connector on the card into four combined data/power connectors.
 
just out of curiosity, what is the benefit of sas drives over ultra320? is it just the smaller drive form factor or are other benefits added?
 
Originally posted by: bob4432
just out of curiosity, what is the benefit of sas drives over ultra320? is it just the smaller drive form factor or are other benefits added?
Click to expand...

Basically, the drives are the same.
The Fujitsus we have are just plain SCSI drives with a different interface. The SAS connector looks just like a regular SATA connector, but it's keyed slightly differently so you can't attach an SATA cable to it (we tried 🙂).

The real benefits are:

1. Smaller cables. Making flat ribbon SCSI cables look neat in a server is time-consuming and sometimes highly difficult in cases such as an SC5200, where you have to route the cable down the side of the CPU heatsinks, which interferes with the plastic airflow ducting.

2. Greater interface bandwidth. I forget the exact figures, but it's supposed to be able to remove the 320MB/sec ceiling, which can be experienced when you are running multiple drives together on one controller.

3. Interoperability with SATA drives - with a simple cable change, the same controller can support SATA drives. This is probably the best thing, IMO. You could buy the controller card and use it with your existing SATA drives, and then simply buy SAS drives if you want to upgrade.
 
Originally posted by: Phil
3. Interoperability with SATA drives - with a simple cable change, the same controller can support SATA drives. This is probably the best thing, IMO. You could buy the controller card and use it with your existing SATA drives, and then simply buy SAS drives if you want to upgrade.
Click to expand...

agreed, this does seem to be a pretty cool feature. does the controller have regular sata connectors or are they keyed to the sas type?

i can also understand about the cabling size being an issue, with so many drives.

 
Originally posted by: bob4432
Originally posted by: Phil
3. Interoperability with SATA drives - with a simple cable change, the same controller can support SATA drives. This is probably the best thing, IMO. You could buy the controller card and use it with your existing SATA drives, and then simply buy SAS drives if you want to upgrade.
Click to expand...

agreed, this does seem to be a pretty cool feature. does the controller have regular sata connectors or are they keyed to the sas type?

i can also understand about the cabling size being an issue, with so many drives.
Click to expand...

Well, the SAS connector for the card is a bit like a SATA connector and a SATA power connector fused together in a long strip. It has small grips either side to "click" the connector securely into place, and you can't plug a SATA cable into it - they moved the "L"-shaped piece of plastic so the SATA cable won't go in.

Then, the connector splits into four small SATA-sized cables, although in reality, the cables are thinner and smaller than SATA cables. These cables go to an all-in-one data/power connector, which then splits back into a regular Molex for power.

While this is somewhat messy, it does mean that you can use the card in servers, 95% of which don't have SATA connectors on their power supplies. You can't really swap the PSU out, as a dual redundant unit is a tad pricey to be swapping 😉

I'll try and get a picture on Monday to show you what I mean, it's difficult to explain in writing 🙂
 
Originally posted by: Phil
Originally posted by: bob4432
Originally posted by: Phil
3. Interoperability with SATA drives - with a simple cable change, the same controller can support SATA drives. This is probably the best thing, IMO. You could buy the controller card and use it with your existing SATA drives, and then simply buy SAS drives if you want to upgrade.
Click to expand...

agreed, this does seem to be a pretty cool feature. does the controller have regular sata connectors or are they keyed to the sas type?

i can also understand about the cabling size being an issue, with so many drives.
Click to expand...

Well, the SAS connector for the card is a bit like a SATA connector and a SATA power connector fused together in a long strip. It has small grips either side to "click" the connector securely into place, and you can't plug a SATA cable into it - they moved the "L"-shaped piece of plastic so the SATA cable won't go in.

Then, the connector splits into four small SATA-sized cables, although in reality, the cables are thinner and smaller than SATA cables. These cables go to an all-in-one data/power connector, which then splits back into a regular Molex for power.

While this is somewhat messy, it does mean that you can use the card in servers, 95% of which don't have SATA connectors on their power supplies. You can't really swap the PSU out, as a dual redundant unit is a tad pricey to be swapping 😉

I'll try and get a picture on Monday to show you what I mean, it's difficult to explain in writing 🙂
Click to expand...

thanks, will be looking forward to the pic. hopefully these sas will really take off and people will start selling their "old" u320 hdds cheap on ebay or here in the fs/ft forums 🙂

did you guys get them for testing or are you going to be switching to them fully?
 
Originally posted by: bob4432
Originally posted by: Phil
Originally posted by: bob4432
Originally posted by: Phil
3. Interoperability with SATA drives - with a simple cable change, the same controller can support SATA drives. This is probably the best thing, IMO. You could buy the controller card and use it with your existing SATA drives, and then simply buy SAS drives if you want to upgrade.
Click to expand...

agreed, this does seem to be a pretty cool feature. does the controller have regular sata connectors or are they keyed to the sas type?

i can also understand about the cabling size being an issue, with so many drives.
Click to expand...

Well, the SAS connector for the card is a bit like a SATA connector and a SATA power connector fused together in a long strip. It has small grips either side to "click" the connector securely into place, and you can't plug a SATA cable into it - they moved the "L"-shaped piece of plastic so the SATA cable won't go in.

Then, the connector splits into four small SATA-sized cables, although in reality, the cables are thinner and smaller than SATA cables. These cables go to an all-in-one data/power connector, which then splits back into a regular Molex for power.

While this is somewhat messy, it does mean that you can use the card in servers, 95% of which don't have SATA connectors on their power supplies. You can't really swap the PSU out, as a dual redundant unit is a tad pricey to be swapping 😉

I'll try and get a picture on Monday to show you what I mean, it's difficult to explain in writing 🙂
Click to expand...

thanks, will be looking forward to the pic. hopefully these sas will really take off and people will start selling their "old" u320 hdds cheap on ebay or here in the fs/ft forums 🙂

did you guys get them for testing or are you going to be switching to them fully?
Click to expand...

We only really get in hardware that we'll be using in future, and as the controller isn't officially launched until sometime late this year or early next year, we need to test it to destruction first, so we can be confident in shipping SAS systems.

I would imagine that with the SATA interoperability, companies will be jumping on these like they're going out of fashion, especially if they're buying with a desire to expand at a later date.
 
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