Choice between SAS and SATA HD

[AndreaMennini]

Hi,

I'm planning to buy a ML150 G3 server for a Small Office (10 folks) office. It should be a file and print server.

Does ML150 support RAID5 with both SATA and SAS disks? Since cost ratio is 4:1, which is the real difference between them? Are SAS faster than SATA's in a way that I can can account for to my customer, since an array of 4 SATA disks (3 + 1 Hot Spare) costs like 1 bare SAS disk?

Thanks

Ciao

[Neal Bowman · Accepted solution]

AndreaMennini,

There is a reason SATA disks are cheaper than SAS disks. They don't last as long. They should not be installed in a server (this is just my opinion). HP only warrants SATA drives for 1 year, and SAS drives for 3 years. Below are direct quotes from the HP Product Bulletin:

SATA Drives:
HP 3.5" and Small Form Factor (2.5") SATA drives provide the lowest cost per GB targeted for non-mission critical applications with low workloads of 50% or less. All SATA drives offer a one-year limited warranty.

SAS Drives:
SAS drives are enterprise class devices designed to operate 24/7, 365 days/year.

Historically, SATA drives have a MTBF of 500,000 hours with a 20% duty cycle. Putting these drives in a server will push this duty cycle between 80-100%, effectively sending the SATA drive to a much earlier grave.

As your customer what would it cost to be down when a SATA drive fails, and if he can afford the cost after the mfg warranty expires after 1 year.

As for explaining any speed differences to the customer, the SAS drives have 10k and 15k rpm drives available, while the fastest SATA drive can operate at 7.2k.

So, for the extra up-front cost of SAS, you get faster, more reliable drives with a longer warranty.

Hope this helps,

Neal

[Mauro Rusignuolo]

Also, consider SATA II Seagate Disks.
HP uses this frequently.
BARRACUDA series with part number ending with "0NS" that identifies "ES series", has 5 years warranty and built using same criteria used for SAS drives.
but they are slower than SAS.

the cost is a little bit higher than the "normal" sata drives.

I hope this help.

bye.

TJK.

[AndreaMennini]

Ok. Thanks both for your answers.

BTW: my customer has chosen SAS disks.

Ciao