Hi

 

weighing up the pros and cons of using a cache drive. I have two drives i am trying to decide on for the cache drive:

 

1) WD Raptor - 10,000rpm - 75GB - SATA I (150) - 8MB cache

 

2) Maxtor - 7500rpm - 200GB - SATA I (150) - 8MB cache

 

 

 

 

 

A few questions:

 

1) If the cache drive becomes full then how is this handled by unRAID?

e.g i want to know what would happen if i use a 75GB drive as a my cache and i try to upload 76GB in one go?

Does it give an error?

Does it just copy the 75GB and then error out as there is no more space for the remaining 1GB?

 

2) When the schedule to move the data from the cache drive to the protected array is invoked (in the early hours of the morning), what is the biggest limiting factor in the write speed?

 

 

3) Which of the drives would i use? Or should i get a newer SATA II 7200rpm drive?

 

 

thanks!!!

 

details of my hardware can be found here : http://lime-technology.com/forum/index.php?topic=5198.msg48905#msg48905  ... i am still playing with final setup as i keep reading more and then "improving" how things are going to be setup

weighing up the pros and cons of using a cache drive.

 

With the serious speed improvements in the latest unRAID versions, using the cache drive became kind of meaningless.

Besides, I hate the idea that some of my files will just sit there unprotected for half a day or so.

Therefore, my personal advice would be: forget about that cache drive.

 

1) If the cache drive becomes full then how is this handled by unRAID?

e.g i want to know what would happen if i use a 75GB drive as a my cache and i try to upload 76GB in one go?

Does it give an error?

Does it just copy the 75GB and then error out as there is no more space for the remaining 1GB?

 

data will be copied until the filesystem is full. Then it will error out on the final file.

 

2) When the schedule to move the data from the cache drive to the protected array is invoked (in the early hours of the morning), what is the biggest limiting factor in the write speed?

 

The same issue with writing directly to the protected array in the first place.

With recent improvements this may not be such an issue.

 

3) Which of the drives would i use? Or should i get a newer SATA II 7200rpm drive?

 

How much data do you need to move at one time? and How fast?

 

 

If you plan to move over 75gb of data, go with the larger drive.

But first try moving your data without the cache first and see if it's really needed.

I still have not bothered with a cache drive.

thanks both for your replies. Opted not to go for the cache drive.

 

Just got my PLUS key.... cant wait to get cracking on this over the weekend!