I have just purchased an entire new motherboard & ram as my current motherboard only has 1xPCIe16, 2xPCIe1, and 1x1pci_legacy

 

I need a x16 for my GPU in XEN passthrough, but I also need to use a Supermicro SASLP-MV8 which has a x4 connector

 

I have just run across a - 1X to 16X Powered PCI-E PCI Express Riser Card Extension USB 3.0 - which appears to let one use a x16/8/4/1 card in a x1 slot.

Is it OK to run 8 Hard-drives on Supermicro's SASLP-MV8 in a PCIex1 slot using these?

 

http://www.ebay.com/itm/1X-to-16X-Powered-PCI-E-PCI-Express-Riser-Card-Extension-USB-3-0-SATA-Cable-/251427575395?pt=LH_DefaultDomain_0&hash=item3a8a405663

 

http://www.supermicro.com/products/accessories/addon/AOC-SASLP-MV8.cfm

 

If so, It appears as if I do NOT need a whole new motherboard/ram

 

THANK YOU

Yes ... HOWEVER, as I assume you're aware, you'll be severely limiting the bandwidth to the card by providing it with only 1 PCIe lane instead of the 4 it's designed for.

 

By the way, with some VERY careful work with a Dremel tool, you don't need the adapter.  If you cut off the end of one of your x1 slots, the x4 card should plug into it with no problem.  Just be CERTAIN you don't mess up any of the electrical connections when you remove the end piece of plastic.

 

... a note on the performance:  With only an x1 slot, the READ performance for typical streaming (i.e. only one drive being accessed) will be normal.    And writes should also be normal - especially if the parity drive isn't on this card.    The biggest thing you'll notice is that parity checks will take quite a bit longer.

 

This is exactly the type of answer I was looking for Gary!  Thank you GREATLY.

 

Given that I only do parity checks once a month (on about 12 GB of data) - I am not certain I am terribly concerned. 

 

Many Cheers!

This is exactly the type of answer I was looking for Gary!  Thank you GREATLY.

 

Given that I only do parity checks once a month (on about 12 GB of data) - I am not certain I am terribly concerned. 

 

Many Cheers!

 

As Gary eludes. the issue is simultaneous access.

 

A typical PCIe x1 card supports 2 drives, so with 2 drives you'd not experience any performance issue during parity checks. But if you are doing I/O to more than 2, especially if you get to 4 or 5, you'll definitely be experiencing the constriction.

 

But if you are accessing one or two disks on this card at a time, you shouldn't notice any decreased performance, even if all 8 are connected. Of course the parity check is the worst situation of simultaneous access.

 

It would be good to have your parity on a motherboard port, and cache on a SASLP port. Cache is not involved in parity checks and it frees up a wider port for an array disk. in general, have full drives that you access less on the SASLP ports. Conversely you want drives that you read from and write to regularly on MB ports.

 

I am not aware of anyone else doing what you are describing. If you do it, would be interesting to see some benchmarks when installing multiple drives on the card.

I am not aware of anyone else doing what you are describing. If you do it, would be interesting to see some benchmarks when installing multiple drives on the card.

 

I decided to keep the Asus board but tested this on our work rig.  With 4 data drives on the machine we have noticed no slowdown in access or writes.  We use this machine to do 8 windows backups within a small time frame and 4 Cobian backups.

 

Parity checks are not noticeably slower - usually they take about 4.5 hours and now they take about 5 hours.

 

I do not currently have the ability to check speeds using 8 drives.