Rosewill RSV-S4-X 4 Bay (Port Multiplier) Enclosure - $82.99 + shipping

[poofyhairguy]

Here is a great deal that made me wish I had a few extra dollars sitting around. Here is an open box 4 bay PMP enclosure for a little over half price:

 

http://www.newegg.com/Product/Product.aspx?Item=N82E16816132029R

 

The usually go for $149. They can be a great way to add another four disks to your Unraid server!

 

Please someone post if you bite on this!

[Sean_W_Smith]

are there any issues using a device (Port Multiplier) like this with unraid?

 

Sean

[WeeboTech]

I think the hard drives on the PMP(Port MultiPlier) are limited to 60MB/s depending on the controller.

Command vs FIS based switching.  This is a hard ware design situation.

Still plenty of fast enough to serve media without interruption.

[poofyhairguy]

I kinda think of port multipliers like I think of running 4 drives off a PCI card- terrible Parity Check speeds, but overall acceptable performance.

[WeeboTech]

I kinda think of port multipliers like I think of running 4 drives off a PCI card- terrible Parity Check speeds, but overall acceptable performance.

 

It's not terrible, it's about 50,000/kbs to 60,000/kbs.

 

I have done tests of simultaneous multiple drive access. Each worked at 60MB/s.

That's not too bad.

 

I haven't executed the same test in PCI/33mhz but in PCI/66Mhz i was able to achieve 80MB/s simultaneous access on 2 drives.

[Kaygee]

That seems rather unfair, most hard drives will struggle to sustain 60MB/s. unRAID will certainly struggle to sustain 60MB/s when writing.

 

My problems with PMs were unRAID syslogs were noisy due to PMs not being mature technology. Worked OK though. However I didnt like noisy logs because with all the errors you couldnt easily see if there was an issue developing.

 

Three years ago I paid £150 for ten ports and could add another 10 ports for another £70. At the time a similar 8 port RAID card would of been £250. Nowadays probably £120 for ten PM ports vs £75 for 8 real sata ports. 

 

For someone struggling to add more ports to an existing unRAID setup, PMs could be the answer.