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Re: [OT] SATA vs. SCSI



On 2005-10-27T19:33:22-0400, Gene Heskett wrote:
> Our first foray into using a scsi based commercial server resulted in
> its getting converted to ata disks fairly rapidly as the scsi raid
> lost a drive at 2 week intervals.  A single big atapi/eide drive
> turned out to be faster, and a heck of a lot more reliable.

While I feel for you, it's not a good idea to make decisions based on a
single installation.  If you have disks dying every 2 weeks, something
else was up.  Heat would be my first guess.  Seagate, I think, had a
batch of bad SCSI drives recently.

Sign up for an account on http://www.storagereview.com/ and check out
the reliability survey.

I have good luck with IBM (2 GB) and Fujitsu (32 GB) SCSI drives, and
had a Quantum (9 GB) die on me.

> Ditto here at home, I gave up on scsi tape drives about 18 months ago and
> bought a 200GB atapi/eide drive & setup amanda's virtual tapes on it.  It
> has so far, been about 100x more dependable than the scsi tape ever was.

The interface is probably the most reliable thing on a tape drive.  Are
you comparing the same drive, same brand but just different interfaces?

> Now we've gotten into the video server scene, again with the recommended
> terrabyte raid, scsi3-320 or some such based with a 1394B (800
> megabits/second=100 megabytes) interface to the servers, and again scsi is
> being a problem child with an occasional stutter while playing and always
> a missed first word as it starts.

1394B -- array --> scsi --> disk?  How many disks?  Just curious.  I
could not get 1394 to work with Linux, and has to use USB for an
external disk for the enclosure that I picked up after much resarch.

> Put the same program file on a single internal big atapi/eide drive
> and the performance is 100% reading while writing so we put in 2
> drives per server.

If it works for you good, great, it's a cheaper solution.  If you
starting pounding if with multiple users, it may not such a good
solution and you may need more than one spindle to handle the load. I
read one of the postgresql lists that IDE drives apparently claim sync
data immediately while SCSI drives are truthful.  That makes a
difference when you are concerned about data transactional data.

> able to find an rsync workalike that does both branches of the apple
> filesystem so that we can fabricate a darned near realtime, live,
> online, redundant backup in case one server chassis should upchuck
> in the middle of a program playback.
> 
> If anyone has a clue how we can simulate an rsync run between 2 dual g5
> servers at 5 minute intervals, we're all ears.

Suggest you start a new thread on this.


/Allan

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