Cached drive and Parity Drives

[cpluse]

My UnRaid box has been working great so far. I’m about to start having my mac computers backup to the UnRaid 3 times a week. I am still researching the part of not backing up files that have not changed. After I get this completed I will create a 2nd system to back up this unraid box.

 

But my real question. At this time I don’t have any drives that are cached drive. Just 2 Parity drives (2TB 7200). Concerning speed and reliability. Should I update the 2 parity drive to 4TB 7200rpm. Or get a Cache SSD drive? To help with file transfer and backing up the multiple macs in my location.

 

I have 6 2Tb drive install at this time. 8TB total for backup storage. With the size of the cache drive will 240gig SSD be enough. Or get 2 120gig SSD to make it a pool.

With the Parity I should only upgrade is I have the same size drives for it I upgrade to 4TB drive. I will need to make both my parity drive 4tb first then upgrade. For the SSD I wanted to use my Mercury Accelsior since I have space in my riser board. I assume this would help with streaming movies also when needed.   

 

Thank you ahead of time for everyone help.

[wgstarks]

As far as backing up your Macs, TimeMachine runs totally in the background so speeding up transfers isn't really necessary for that. You won't ever notice the extra performance.

 

The SSD cache may give you a performance boost when copying other files TO the array from other machines on your local network. Writing directly to the parity protected array can seem slow if you're just sitting and waiting for the file transfer to complete.

 

Cache drives aren't used when streaming video from the array (unless you have them permanently stored on cache which isn't likely).

Edited May 19, 2017 by wgstarks

[cpluse]

For the Mac it taking me a little longer with Time Mach. I had to do the work around with adding the EEID how-to. It just seem really slow transferring. The other mac already have TM drives so im just backing up from them. Until they fail. I'm just backing up this way until i can fix the issue of adding multiple time machine backups to one folder. 

 

So SSD will take the load of the 2 parity and help make them last long with less stress. Im just getting the concept of how parity drives work. But should i get bigger parity drives or get SSD to help with performance in the long run?

 

 

[Helmonder]

Bigger parity drives are only needed when you have data drives that are bigger then your parity drive (because thrn parity does not work!!)

There is not any sense in having bigger parity drives then your biggest data drive (and since all tour data drives are 2tb the parity drives need to be 2tb to, making them bigger is possibly but it has no advantage whatsoever, everything above 2tb simply does not get used.

Ssd will not "take the load of parity", only of you should decise to make a cache-only share (then the share will only be on the cache drives and not on the data drives and therefor will "take the load of parity"..

The questions you are asking give me an aking feeling wrt hou understanding how unraid works..


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[cpluse]

Ok great!

 

I got it now. Later i will be upgrade my drives to 4TB so i will change out the parity drive then. 

 

Im still learning and if i don't ask i won't learn. 

 

Thanks for the explanation.