I can’t get home. I am stuck here at the coffee shop waiting out the traffic jam after the heavily downpour an hour ago.
It has been an interesting week for me, which began last week when we were testing the new Seagate 3TB Constellation ES.2 hard disk drives. It doesn’t matter if it was SAS or SATA because the disks were 7,200 RPM, and basically built the same. SAS or SATA is merely the conduit to the disks and we were out there maneuvering the issue at hand.
Here’s an account of testing done by my team. My team has been testing the drives meticulously, using every trick in the book to milk performance from the Seagate drives. In the end, it wasn’t the performance we got but more like duds from Seagate where these type of drives are concerned.
How did the tests go?
We were using a Unix operating system to test the sequential writes on different partitions of the disks, each with a sizable GB per partition. In one test, we used 100GB per partition. With each partition, we were testing the outer cylinders to the inner cylinders, and as the storage gurus will tell you, the outer rings runs at a faster speed than the inner rings.
We thought it could be the file system we were using, so we switched the sequential writes to raw disks. We tweaked the OS parameters and tried various combinations of block sizes and so on. And what discovered was a big surprise.
The throughput we got from the sequential writes were horrible, started out with MB/sec lower almost 25% lower than a 2TB Western Digital RE4 disk, and as it went on, the throughput in the inner rings went down to single digit MB/sec. According to reliable sources, the slowest published figures by Seagate were in the high 60’s for MB/sec but what we got were close to 20+MB/sec. The Western Digital RE4 was giving out consistent throughput numbers throughout the test. We couldn’t believe it!
We scoured the forums looking for similar issues, but we did not find much about this.This could be a firmware bug. We are in the midst of opening an escalation channel to Seagate to seek explanation. I would like to share what we have discovered and the issue can be easily reproduced. For customers who have purchased storage arrays with 2 or 3TB Seagate Constellation ES/2 drives, please take note. We were disappointed with the disks but thanks to my team for their diligent approach that resulted in this discovery.
I was wondering if you made any progress on this case, I have a san with 15 3tb es.2 drives and performance on those is TERRIBLE. our old equallogic using 750gb 7200rpm drive is giving out twice the iops and can easily max out 1gbps iscsi interface.
Yes, we have tested the Seagate 3TB ES.2 and we had very poor performance in the inner tracks.
We created several 100GB partitions from the outer tracks to the inner tracks. While the outer tracks recorded reasonable transfer rates, the transfer rates of the ES.2 got worse as we move into the inner tracks. By 700-800GB, 7th partition, the transfer rates were down to single digit MB/sec. We have tested quite a bunch of them, and we got consistent results.
So, we had to keep our WD RE4 2TB for a while until now. We are now shipping our storage solutions with Hitachi 3TB UltraStart 7K3000 and we are OK with it so far.
Overall, we don’t have good experiences with Seagate Enterprise drives. The Barracuda, even though it is not really enterprise, are pretty good.
Thanks for reading my blog. All the best!
Can you tell me which firmware version was running on the drives you tested with ?
Dell for example provides 2 updates, one of them as a key sentence in it (first and last fix listed seems interesting):
* Firmware Version RS0C *
Seagate 7.2k SAS 3.5″, version RS0C, for drive model number ST33000650SS (3TB)
Fixes and Enhancements
Corrected an issue that could cause drive to enable low power write mode
Corrected an issue where idle timers where not initialized when drive transitions from stop to active mode
Improved drive error handling
Improved drive log page counters
Enhanced priority of servo calibrations based on temperature readings
Improvements to Sequential Read and Write performance
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91K8T – HD,3T,NL6,7.2K,3.5,S-MR,E/C