This is a 4 port SATA\SAS card. 

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16816102140

 

I know that Unraid only supports IDE and SATA, but is there a reason why a SAS drive would work?  Escpecially with a card like this??  SAS Cache Drive Anyone?  Hmmmm?

 

And, I've used Promise Cards heavily in the past.  I've found them to be very reliable. 

Do you plan to purchase a SAS drive.

I'm not against it, I have two 10,000 RPM SAS drives for my RAID-1 Mirror within my workstation.

It's just the cost vs performance level for what unraid gives you may not be worth it.

Are you ready to spend $200 for a 300GB sas drive when you can purchased a 1TB SATA drive for the same money.

Unless you are doing allot of random I/O's from many different processes, I'm not sure it would be worth it.

 

If it were a database server yes, but a home based PC file server.. You can easily get away with using SATA.

Weebo, I see your point of course.  I was thinking about SAS for the cache drive.  And then using the other 3 ports for standard SATA drives. 

 

Earlier in the night, I had came across this thread.  Which got me thinking in a cache drive sort of way. 

 

http://lime-technology.com/forum/index.php?topic=1891.0

 

A SAS drive would be far less exotic than the Gigabyte RAM card you linked to.  And, if you exclude the card's price, because I am going to need more SATA ports soon anyway; its a cheaper solution than the Gigabyte card, once you add in the RAM that would have to be purchased, and I bet it would offer comparable speeds.  I know it would offer a ton more capacity for cache depending on the size purchased. 

I have to frank and blunt. I don't think a SAS drive in the cache drive context is worth your money.

A SATA 1TB 7200RPM Seagate w/32MB cache will work well enough.

 

I thought the purpose of the ramdrive for cache was to minimize a spindle. (Which was my purpose, but not for the purpose of a cache).

 

A SAS drive has the advantage of SCSI's  disconnect feature.

I.E. a command can be sent on the bus and the controller can disconnect from that command to issue another.

The drive will then return a status after the command has been completed.

This is why SCSI drives are used in enterprise server configurations. Many outstanding I/O's can be performed

 

I think with the nature of unRAID and general home use, a good performance SATA drive and controller combination with NCQ will suffice.

http://en.wikipedia.org/wiki/Native_Command_Queuing

http://en.wikipedia.org/wiki/Tagged_Command_Queuing

 

Let me re-iterate The controller is a fine controller, use of a SAS drive may not be worth the price of the drive itself because you'll get more capacity (and also more speed) by spending on a good performing 1TB drive probably for close to the same amount of money.

 

Now if you happen to have spare SAS drives laying around.. that's another story.

 

My use of the Gigabyte Ram drive is a totally different thing. I use it as an NFS mount point for some of my servers that write log messages every few seconds. Writing to battery backed ramdrive that survives a reboot saves head movement and wear/tear on the machines logging the messages.

 

If I'm missing something here on your thoughts for the SAS drive as a cache drive, vs a SATA drive, please elaborate.

I own both I can tell you a 300GB SAS drive is not as cost effective as a 1TB SATA drive.

 

What is it that is being written to the Cache drive that requires that level of performance.

Plus you have to ask, are the drivers for that card available in unRAID?.