I am considering setting up a Plex Sever on my unRAID server. I currently do not have a cache drive.

 

Does it made more sense to buy a larger 250GB SSD drive and use it for both PMS and a cache drive or would it be better to buy a smaller 64GB SSD drive and mount it on startup and then get another 3TB drive as a warm spare in place of a cache drive?

 

It seems like there have been differing opinions on this subject so please feel free to list all the pro's and con's.

If you can afford a drive large enough for your plex library and for your largest expected daily cache writes, then I'd go consolidated to save MB ports.

 

If you can afford a large enough SSD, and/or you want to use a cache large enough to also double as a warm spare should any array drive fail (so it should be the same size as your parity or larger) then you might consider a drive for each function.

 

The pro's and con's are really a personal choice and depend on your situation and use case.

I recently went with a 256GB SSD for my cache drive and also use it for plex, sickbeard etc...  I thought it made more sense that way because of the consolidation and the drive size should be  adequate for a long while.  Also, Plex is amazing...

Oh and keep in mind if you are generating plex index files your library will grow quite large.  How large?  depends on your library. 

Are the plex index files the movie previews?

So I found a spare 320gb 7200 rpm WD Black drive in a spare computer. Besides speed loss is there any other disadvantage to using a 7200 rpm drive vs SSD as a cache drive?

The disadvantage would be that if you're using a spinning drive for plex to "live" on then it will never spin down because that's just how plex is.

 

The other issue is that SSD's are inherently more reliable than spinners so make sure you back it up once in a while so in case in anything goes wrong with the black then you can make a quick recovery.

 

Speed wise I don't think it'll be that big of a difference but I honestly have only tried it the SSD way.

 

also about index files... Those are basically chains of screenshots that streaming players like the roku will use to help track and seek in the video as you skip or fast forward etc in the video.  I wouldn't bother with it unless you have weaker client devices that will actually use it or need it.

Thanks misterbeetz! I think I will just use the spinning drive as it is hard to pass up free and then when it dies I will go SSD.

This should also give you time to evaluate usage and storage needs for when you decide to go SSD.

Yeah very true.