Exsys EX-3508 - working?

[bigbear]

Hi Guys,

 

im very impressed with your software. So ill build a NAS with it.

 

I was thinking of using this controller:

 

http://www.exsys.ch/index.php?main_page=product_info&cPath=36_39&products_id=702

 

(non-raid, 8 ports, sil3132-chipset)

 

Is anyone using this controller? Its under 100 EUR, so quite cheap.

If noone is using it, the sil3132 should work, shouldnt it?

 

thanks for your help

[prostuff1]

It should work, but the speed of 8 drives on the PCIe x1 lane will not be great at all.  It would be fine for accessing 3-4 drives at the same time, but any more than that and speed will suffer.  This should not be a huge deal, except during a parity check.

 

A better solution, if you have an available PCIe x4 or greater slot is the Supermicro SASLP SATA card.  This card works in a PCIe x4 slot or greater and will allow for 8 drives to be connected using special SAS cables. 

 

Do some searching in the forum for the card and info related to it.

[bigbear]

thanks prostuff1!

 

that card is indeed much better and only a couple of euros more, but not that easy to come by in germany.

 

i will also be using an 8 port pci-x card (in a 32bit PCI Slot) so im curious: Shouldnt the parity check be made on the fly when writing a file to the array (if im not using a cache drive)?

 

so would the write speed via gigabit-lan be increased if i use a pci-express 4x controller instead of the pci-x controller in the standard pci-slot?

 

[prostuff1]

parity is indeed calculated on the fly when adding data to the server.

 

Many of us do a monthly parity check to make sure that all drives are working well and nothing is acting up.

 

With 8 drives already on the PCI bus you are going to have slow parity check and rebuild times already.  If you add a drive or a drive fails and you have to rebuild it will take longer to do so because of the PCI bus.

[BRiT]

Here's a lot of information on PCI-X and PCI-Express and PCI buses: http://lime-technology.com/forum/index.php?topic=7520.0 and also http://lime-technology.com/forum/index.php?topic=7526.msg72896#msg72896

 

The limitation is beyond just parity checks. The limit occurs in the following situations, during parity builds, parity checks, failed drive situation, drive rebuilds, simultaneous writes, and simultaneous reads.