What SATA card should I buy if I don't want the RAID?

[Atheus]

I want a cheap PCI-X or PCI SATA controller card for my home 'server' so I can expand my storage space without buying expensive SCSI drives. I don't want any RAID features though - I hear Linux software RAID is much faster than 'fakeRAID' setups, and real RAID is too expensive.

What are my options? Will I get any benefits from PCI-X over PCI if I'm using 2 HDs in RAID 1? Does it even matter which one I buy?

 

[corkyg]

"Too expensive" is a relative term unless you quantify it. I have used this card, and it is excellent - non-RAID as you specified.

Newegg

But, apparently it is not happy with Linux. I wouldn't know - that's not my thing. It works great in XP.

 

[Zepper]

RAID just comes along for the ride with most SATA, you don't have to use it. I'd try an inexpensive Syba with the Silicon Image chip on it - well under $20. shipped. There are several others on a red PCB that all look like the same board. The Rosewill is the least expensive at about the same price at the Syba. So if you have a red mobo, you can have a matching controller... All are S-I based.

Looks like that Adaptec has a Silicon Image chip too - wonder how Adaptec managed to screw that up for Linux as S-I support is in all recent kernels?

PCI-X should make little diff. in software RAID-1 as the data will only be crossing the bus at single drive speed anyway. Now, RAID-0 or 0+1 are different stories.

.bh.

 

[Madwand1]

Actually, a good RAID 1 implementation should be able to "stripe" reads, and with just that, using decent drives, etc., you could saturate PCI.

 

[d3n]

I know its not the definition of cheap but this is half the cost of other current SAS offerings and you do get RAID.

adaptec SAS controller

You can trhow regular SATAII drives in and it will be alright. If you get over 4 or 5 SATA disks there should be little diffrence from an SAS setup.

 

[Blain]

Puget Custom Computers...
"<a target=_blank class=ftalternatingbarlinklarge href="http://www.pugetsystems.com/alternate_os.php">Configuration Limitations
Our experience with Linux has led us to make only two limitations to our offer -- systems sold intended to run Linux must use a nVidia video card,
and if you want RAID, it must be run from one of our offered 3Ware RAID controllers.</a>"

 

[Zepper]

Oh, so they make you buy a fancy controller to reduce support headaches for themselves. Well, thaaaank you! :roll:

.bh.

 

[Blain]

Originally posted by: Zepper
Oh, so they make you buy a fancy controller to reduce support headaches for them. :roll:

.bh.

They must be in bed with nVidia too.

 

[Atheus]

Thanks for the replies.

According to this there is support for most of the chipsets out there, but the driver situation is more complex than I thought, especially if I want to install on a software RAID volume. Does anyone have any experience with this?

Maybe I would be better off with regular IDE... unless I get PCI-X I'll only get 133MB through the bus anyway. I guess I might saturate that with 2 of the new 320GB perpendicular storage Seagates, but would I really notice the difference? I dunno...

The problem is the IDE on this old serverworks board is only 33MB, as it's designed to use the onboard SCSI, so I'll still want a contoller card. And I am _not_ buying 600GB worth of 10K SCSI

 

[Zepper]

With software RAID 1 (once the mirror has finished its creating) like I said there is only a single drive speed worth of data moving across the PCI bus at any given time. Unlikely to saturate. Normal reads should be from only the single primary drive in the RAID-1 volume as well. I can't see anyone bothering to stripe a RAID-1 pair unless they have some really unusual software. With software Raid-0 or O+1, you can get up to two drive speeds worth of data trying to cross the bus at a time, so there is the potential of saturating there.

.bh.

 

[Madwand1]

http://www.intel.com/performance/deskto...m_technologies/storage_performance.htm

"Note: RAID 1 provides performance benefits in most tests due to the ability to "split reads" between disks. In effect, this means half the data can be read from each disk improving read throughput. However, in some configurations the File Copy test may show slightly lower scores than a single-drive configuration. This is because RAID 1 requires writing of data to each of the two disks and does not complete the write until both disks are done."

 

[Lord Evermore]

Originally posted by: Zepper
With software RAID 1 (once the mirror has finished its creating) like I said there is only a single drive speed worth of data moving across the PCI bus at any given time. Unlikely to saturate. Normal reads should be from only the single primary drive in the RAID-1 volume as well. I can't see anyone bothering to stripe a RAID-1 pair unless they have some really unusual software. With software Raid-0 or O+1, you can get up to two drive speeds worth of data trying to cross the bus at a time, so there is the potential of saturating there.

.bh.

With real software RAID1, when writing you would actually be sending twice the data over the bus, since a complete copy of the data has to be sent to each drive by the OS. It's not just sending one copy to the controller and letting the controller duplicate it to the drives. So writes will always be having to transfer twice what a single drive does, possibly saturating the bus depending on the throughput of each drive.

With the consumer controllers that are driver-based, it should be only one copy being sent to the controller, as it would be with a fully hardware RAID controller.

When doing reads performance ought to be close to twice the speed of a single drive regardless of it being software or hardware controlled, because it's reading half the data from each drive, in a good RAID1 implementation, so it could saturate the bus. The data isn't actually "striped" when it's written with RAID1, but it is read back as if it were striped in order to improve read speed.

I don't know if actual software RAID such as you get with Windows Server versions or with Linux soft-RAID actually implements that read feature.

 

[Cerb]

Originally posted by: Zepper
Oh, so they make you buy a fancy controller to reduce support headaches for themselves. Well, thaaaank you! :roll:

.bh.

I've never lost a filesystem except to software RAID. Three times. In Linux. They have good reason (all were RAID 5, BTW).

As for what to buy: if it's got a Silicon Image chip (typically 3112, 4x have 3114), you're good to go.