So I have done some research and determined that its not possible to add external USB 3drives to the array un unRaid, what about eSata drives? I am looking at an 8 bay mediasonic JBOD enclosure that supports both USB 3 and eSata, would I be able to add these disks to my array?

So I have done some research and determined that its not possible to add external USB 3drives to the array un unRaid, what about eSata drives? I am looking at an 8 bay mediasonic JBOD enclosure that supports both USB 3 and eSata, would I be able to add these disks to my array?

You probably would be able to - but I don't know positively - single drive definitely.  But you would definitely loose parity check speed using a port multiplier.  I get a 25% reduction in speed using my SAS expanders and they should be faster than a Port Multiplier.  So expect at least a 25% reduction probably more.

I run two drives over eSATA without speed reduction (30mb/s write, 80-100mb/s read).

 

I use a NexStart HX4 with two drives in it over an eSata port with port multiplier.

 

I just posted asking if USB 3.0 would be possible, as I could use 3-4 drives per enclosure without speed hit.  USB 3.0 enclosure with multiple drives will not work?

I run two drives over eSATA without speed reduction (30mb/s write, 80-100mb/s read).

 

I use a NexStart HX4 with two drives in it over an eSata port with port multiplier.

 

I just posted asking if USB 3.0 would be possible, as I could use 3-4 drives per enclosure without speed hit.  USB 3.0 enclosure with multiple drives will not work?

USB 2.0 or 3.0 won't work as array drives in unRAID.  Not sure unRAID even has drivers for USB 3.0.  eSata works and as long as the drive count is low you won't get much reduction. 

 

Your 100MB/s reads were they during a parity check?  Were they all the same class of drive in your array as in are they all 1TB platter drives?

 

If you are talking reading from a single disk at a time via eSata then I wouldn't expect ANY reduction in speed.  I was talking about speeds during a parity check or when multiple drives are accessed at a time.

My parity check speed averages a bit over 90MB/s, but varies 75-100+ through the check.

 

Individual drives are hitting higher speeds than 100mb/s read speed but not much higher on sustained single-drive reads.  I have a large variety of drives and sizes in my 20-disk array.

My parity check speed averages a bit over 90MB/s, but varies 75-100+ through the check.

 

Individual drives are hitting higher speeds than 100mb/s read speed but not much higher on sustained single-drive reads.  I have a large variety of drives and sizes in my 20-disk array.

Thanks.  So two drives are NO problem for port multiplier.  Using 8 drives in external cage should have a reduction in parity check speeds but as long as you hold simultaneous drive access to 2 to maybe 4 drives regular reads and writes would most likely work very well to no noticeable difference.

I would think 8 drives would make for some extremely slow parity checks, and with 4tb drives already taking so long, you will want to think whether you are willing to take that hit or not.

 

I might add a third drive to my HX4 enclosure as I am out of space now, if I do, I will report back my parity check speed for you.

 

*edit* It might also impact your write speeds?  Someone else would need to chime in on that.  If I add the third drive I will let you know any write speed impact I get.

It might also impact your write speeds?  Someone else would need to chime in on that.  If I add the third drive I will let you know any write speed impact I get.

It should not impact single write operations, as you would still only be involving 2 spindles. Multiple drive writes from different clients wouldn't be impacted until you saturated the Esata link, similar to a parity check. Probably not something you would run into.

I had a 4tb pre-cleared drive ready to go, so I threw it in my NexStart HX4 eSata enclosure bringing it up to 3 drives on a single eSata port.

 

Running my parity check, it has dropped to 36MB/s, so just over 30hr parity check on 4tb.  This is early parity check, I will try to monitor it throughout in case the speed changes.

 

I would be concerned over parity check speed over 8 drives on single eSata.....

 

 

I had a 4tb pre-cleared drive ready to go, so I threw it in my NexStart HX4 eSata enclosure bringing it up to 3 drives on a single eSata port.

 

Running my parity check, it has dropped to 36MB/s, so just over 30hr parity check on 4tb.  This is early parity check, I will try to monitor it throughout in case the speed changes.

 

I would be concerned over parity check speed over 8 drives on single eSata.....

So would I with that big a drop and just 1 drive - wow.

I found an older post talking about 1, 2, 3, and 4 drives through a single eSATA port, and my numbers for 3 line up pretty well.

 

That reported that adding a 4th drive would drop it to about 10MB/s.  So if each drive drops performance by about 1/3rd, you won't have much left after 8 drives!

 

To be more precise, 0.15MB/s parity check.....