SATA vs ATA?

An anonymous reader asks: "I have a client that needs a server with quite a bit of storage, reasonable level of reliability and redundancy and all for as cheap as possible. In other words they need a server with a RAID array using a number or large hard drives. Since SCSI is still more expensive than ATA (or SATA), I'm looking to using either an ATA or a SATA RAID controller from Promise Technologies. While I had initially was planning on using SATA drives, I have read some material recently to make me rethink that decision and stick with ATA drives. What kind of experiences (good and bad) have people had with SATA drives as compared to ATA drives, especially in a server type environment?"

Comments

Dangers of using ATA or SATA for Raid

[DocSponge]

You may want to read this whitepaper and see what they have to say about using ata or sata drives in a raid configuration. It is possible, due to the use of write-back caching, to lose the integrity of the raid array and lose your data eliminating any intial cost benefits. To quote the paper:

Though performance enhancement is helpful, the use use of write back caching in ATA RAID implementations presents at least two severe reliability drawbacks. The first involves the integrity of the data in the write back cache during a power failure event. When power is suddenly lost in the drive bays, the data located in the cache memories of the drives is also lost. In fact, in addition to data loss, the drive may also have reordered any pending writes in its write back cache. Because this data has been already committed as a write from the standpoint of the application, this may make it impossible for the application to perform consisten crash recovery. When this type of corruption occurs, it not only causes data loss to specific applications at specific places on the drive but can frequently corrupt filesystems and effectively cause the loss of all data on the "damaged" disk.

Trying to remedy this by turning off write-back caching severly impacts the performance of the drives and some vendors do not certify the recovery of drives that deactivate write-back caching so this may increase failure rates.

Losing data on an ata raid array happened to a friend of mine and I wouldn't advise using something other than SCSI without understanding the ramifications.

Best regards,

Doc

I made a new years resolution to give up sigs...so far so good!

Client/Server

[soundsop]

I have a client that needs a server.

On a related note, I was having dinner at a restaurant and my waiter asked me for a recommendation for a good email program. So I guess it turns outs that I have a server that needs a client.