Which 2.5" laptop disk would be the best (fastest) choice for a cache drive?

One of the Western Digital Blacks.

 

http://www.amazon.com/Western-Digital-WD5003AZEX-Frustration-Free-Packaging/dp/B008968L6M

That is not a 2.5" disk.

I like the seagate momentus XT drives.

7200 RPM and a built in SSD cache.

 

Whoops! I pasted the wrong one.

 

http://www.amazon.com/Scorpio-Black-Cache-Mobile-WD5000BPKT/dp/B004LR1RPK

 

 

and for comparison.

 

http://www.amazon.com/Seagate-Momentus-Solid-Hybrid-ST95005620AS/dp/B003NSBF32/ref=sr_1_1?s=electronics&ie=UTF8&qid=1346858198&sr=1-1&keywords=momentus+xt

 

Frankly if I had a laptop, I might upgrade the laptop with this drive or an SSD, then use the latop's current drive in my unRAID server.

 

and for comparison.

 

http://www.amazon.com/Seagate-Momentus-Solid-Hybrid-ST95005620AS/dp/B003NSBF32/ref=sr_1_1?s=electronics&ie=UTF8&qid=1346858198&sr=1-1&keywords=momentus+xt

 

Frankly if I had a laptop, I might upgrade the laptop with this drive or an SSD, then use the latop's current drive in my unRAID server.

 

 

I don't have any of the Momentum drives (I have stopped buying Seagate consumer drives), but if I understand how it works correctly, it really wouldn't help much as a cache drive on unRAID.  It's my understanding that it caches your most frequently used files on the (very small) SSD portion.  As a cache drive, the files would change daily and you shouldn't really have any "most used files", so there would be no benefit.

 

Correct?

If you have APPS on the drive, it could help. If you store allot of other files on the drive all the time it could help. (like I do).

 

Consider this. How often do you think the superblock is read and written to?

 

That will be cached. You would be surprised how caching just the directory and superblock could possibly improve performance on a busy drive.

 

For unRAID it may not be that big of a deal unless you had allot of files on the cache drive that were there all the time and accessed often.

That's your benchmark. For normal cache, it's minimal improvement, for an apps drive it's an improvement.

 

on my DJ laptop, the Momentus hybrid makes a world of a difference with all of the directories and superblock information that is read over and over.  There's no way the 4GB SLC cache could cache 500MB of mp3's, but there's a world of a difference when I have to scan them in deep directories.