SATA vs SAS IOPS query

[Steve21]

Morning All,

 

Just wondering if I'm missing an obvious one or whether this is right, If I'm looking at using 7.2k SATA for DR purposes as long as I'm not hitting any IOPS cap would you actually notice any difference in speed on the VMs?

 

Just been having a flick through other sites and seems only argument against them normally is they aren't fast enough for IOPS for huge systems, and that they aren't designed for business usage for constant hits etc, but as this would only be for DR seems a shame to spend lots on it if it's not needed.

 

Thanks,

Steve

[synaesthesia]

There is no difference between 2 identically specced SATA or SAS drives, performance wise, either in read/write or IOPS terms; the difference is reliability.

[mjs_mjs]

There are a few technical differences : SAS uses the SCSI command set to control the drives where as SATA uses the ATA. The SCSI command set has more features for enterprise storage. SAS also have A and B ports meaning a drive can be accessed by two controllers in a redundant configuration, or use multipath tech.

 

For workloads such as DR where you write constantly for extended periods of time, you probably wont see any difference in speed, and the cost performance benefit means the SATA drive probably preform better for the cost. For IOPS, different drive combinations and different firmware versions will give different results for different workloads (it's an art to pick the highest performance combination).

 

If you want to know about consumer grade hard drive failures when used in datacenter like conditions under high load check out this white paper from none other than google http://static.googleusercontent.com/media/research.google.com/en//archive/disk_failures.pdf (it's a few years old but still relevant).