Different types of SFF-8484 to SATA cable?

[trojanfoe]

Hi all, I currently run a home Linux server using Linux software RAID-5 (/dev/md) but I want to increase performance so I have bought a cheap SAS MegaRAID 8408e and a SFF-8484 to 4 x SATA cable (from China). However I cannot see any physical drives. I have managed to update the firmware on both the RAID card and the drives (Samsung HD501LJ - to CR100-13). I have also tried the different SFF-8484 slot on the card, so I don't think it's a problem with the connector on the card.

I remember reading a review of a different card that I think used the same cable and the reviewer mentioning that the card required cross-over wiring to work? Does this ring any bells with anyone?

Thanks in advance,
Andy

 

[time]

No, the interface is shared with SATA. If it doesn't work, you can count on the controller being a dud. Sorry.

What aspect of software RAID-5 performance was lacking? Writes are most likely to be a problem because the algorithms usually default to Write-Through, which kills throughput in this mode.

Otherwise, you will be struggling to improve on Linux soft RAID by moving to a low-end hardware controller. Modern CPUs are just too powerful.

 

[trojanfoe]

Thanks for the reply. Why would you suspect the card over the cable? The card 'works' in as much as the WebBIOS functions and I have been able to examine all of its attributes via the Linux driver and even update the firmware within Linux using MegaCLI. If it's broken then I will get a refund (eBay/Paypal), but I want to be sure it's the card that's broken.

To be honest I don't have a problem with Linux software RAID performance - I was toying with the idea of installing FreeBSD and didn't like the software RAID options that would be required.

 

[Chewy509]

I was toying with the idea of installing FreeBSD and didn't like the software RAID options that would be required.

What's wrong with ZFS on FreeBSD? It'll give you the RAID component, plus a few other nice features like checksumming on all files?

 

[Stereodude]

Do you have a link to the cable you bought? There are two types, and one of the types won't work. I think you want the crossover variety.

 

[Stereodude]

You want the SFF-8484SAS connector on the host side, not on the target side.

 

[LunarMist]

You want the SFF-8484SAS connector on the host side, not on the target side.

Yeah, the other way would be rather odd, maybe for an enclosure?

 

[time]

Wow, I didn't read the OP properly at all. I really need to restrict helpful comments to the right side of midnight. Sorry.

 

[trojanfoe]

Do you have a link to the cable you bought? There are two types, and one of the types won't work. I think you want the crossover variety.

Here's the link: cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280572060952&ssPageName=STRK:MEWNX:IT

 

[Stereodude]

The description on that cable looks correct. Perhaps what they shipped doesn't match the description.

 

[trojanfoe]

The description on that cable looks correct. Perhaps what they shipped doesn't match the description.

You mentioned 'crossover wiring' earlier - how would you recognize that in an item description.

 

[time]

Looks like that cable is incorrectly wired. This user had exactly the same cable and it failed to work with their Perc 5/i.

The same thread says the DealExtreme version works, if that's any help.

 

[Stereodude]

You mentioned 'crossover wiring' earlier - how would you recognize that in an item description.

Well, it says it's for a SAS controller (host) to 4 SATA drives (target). You need a host to target cable, so it should work. However, the seller might not know what they're selling or you got shipped the wrong thing.

 

[trojanfoe]

Great stuff - thanks guys. The seller of the card has kindly offered to send me a SAS cable (that he says will be compatible with my SATA drives), so I'll take it from there.

Cheers,
Andy