Finally, those SCSI/SATA performance numbers.
Comparing yesterday's "primary storage" with today's Serial ATA I know, I'm months and months late providing this data, but here it is... The point here is that the SATA drives on the market today perform as well as the SCSI...
December 6, 2004
Comparing yesterday's "primary storage" with today's Serial ATA
I know, I'm months and months late providing this data, but here it is...
The point here is that the SATA drives on the market today perform as well as the SCSI drives that we were
sold 5 years ago for "core data center" use. Granted data usage has changed, but enough that yesterday's
main storage standards aren't good enough for primary storage today? Take a look at the numbers culled
from the manufacturer's own data sheets, and you decide.
So where this data comes from. I took the data sheets for the drives named, found key performance
information, and compared them. The SCSI drives are older (3-5 years ago) models that were sold as "data
center storage" at the time they were popular, and the S-ATA drives are new today. Some vendors in the
storage industry want to tell you that Serial ATA is inferior by definition, these numbers should show you
that is just not true as a valid blanket statement. They are lower performance than SCSI drives
available today, but the numbers show they are data center/primary storage quality. Only in MTBF (for
Seagate) did we see a significant difference that was not in the Serial ATA drive's favor. In fact, the
only major difference in SCSI's favor seems to be years of warranty.
As always, I have to say that there are some applications that benefit from the performance and added
management functionality of newer SCSI drives, but for most applications, Serial ATA is good enough, particularly when combined with RAID 5.
Maxtor/Quantum:
Atlas II 4.5 GB SCSI | Maxline III SATA | |
Seek Time (Avg Read) | 8 ms | 9.3 ms |
RPMs | 7200 | 7200 |
Transfer Rate | 40 MB per second | 150 MB per second |
Buffer size | 512 KB | 16 MB |
* Interestingly, the data sheet did not have MTBF values for the Atlas II.
Western Digital
Vantage 9 GB SCSI | Raptor 36.7 GB SATA | |
Seek Time (Avg Read) | 6.6 ms | 5.2 ms |
RPMs | 10000 | 10000 |
Transfer Rate (buffer to host) | 80 MB per second | 150 MB per second |
Buffer size | 2 MB | 8 MB |
MTBF | 1,200,000 | 1,200,000 |
Seagate
Barracuda 180 GB SCSI | Barracuda 200 GB SATA | |
Seek Time (Avg Read) | 7.6 ms | 8.5 ms |
RPMs | 7200 | 7200 |
Transfer Rate (to-from disk) | 36.1 MB per second | 58 MB per second |
Buffer size | 4-16 MB | 2-8 MB |
MTBF | 1,200,000 | 600,000 |
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