IDE Questions

[mazultav]

Hello. My miniITX mobo has 2 IDE connectors on it. I'm only going to run 1 parity and 1 data drive initially due to money problems. Sould I have one HD on each cable? When I add more drives can I daisy chain them? What about master/slave settings? thanks.

[Joe L.]

Hello. My miniITX mobo has 2 IDE connectors on it. I'm only going to run 1 parity and 1 data drive initially due to money problems. Sould I have one HD on each cable? When I add more drives can I daisy chain them? What about master/slave settings? thanks.

Probably won't matter... might be very tiny bit faster with one disk on each IDE controller/connector, but odds are you won't notice it.

 

I personally would set the disks to cable select... it really does not matter. Master/Slave would also work.  When you add a new drive you can use any spare connector on either cable.  The assignment of a specific physical drive to a slot in the logical unraid array occurs on one of the unRaid config web-pages.

[mazultav]

Thanks Joe. Your super help full. Its nice to see a forum that actually helps folks and you just don't get the usual search n00b! comments.

[WeeboTech]

Always "try" to keep each IDE drive on it's own channel.

 

The reason is, only one drive can be communicating at a time on a shared IDE channel.

Normally this is not too much of an issue.

However, if one drive goes south, it can hang the whole channel.

With unRaid it may not be too much of an issue, but with Raid-5 it it is.

 

Once I was using software Raid-5 and one drive failed, it took down the whole channel causing a 2 drive failure, thereby messing up the whole raid volume.

 

So when possible, perhaps consider adding in an additional promise controller or a Sata controller so that your drives are point to point rather then sharing a channel.

 

 

 

 

[kraquen]

I believe this is a huge issue with unraid during writes.. every write to the data drive also has to write to the parity drive.  When on the same IDE chain, the write performance seems to be halved.

[BillK]

mazultav,

 

Although you probably won't know see a huge difference in performance, I'd start with your parity drive on one IDE connector/cable and your single data drive on the other (i.e., I'm assuming no CD drive).  Then, when you add your second data drive, place it one the same cable as the first data drive (since all writes, as kraquen points out, involve a data drive AND the parity drive).  The third and last data drive has to go on the parity cable, but you will likely run out of room/power/cooling in your miniTX case before that happens.

[Peregrine]

mazultav,

 

Although you probably won't know see a huge difference in performance, I'd start with your parity drive on one IDE connector/cable and your single data drive on the other (i.e., I'm assuming no CD drive).  Then, when you add your second data drive, place it one the same cable as the first data drive (since all writes, as kraquen points out, involve a data drive AND the parity drive).  The third and last data drive has to go on the parity cable, but you will likely run out of room/power/cooling in your miniTX case before that happens.

 

<AOL> Me too!</AOL> 

 

Seriously, I do want to endorse this - this is probably the best way to use IDE for unRAID, as it gets around the "one-drive-per-channel-at-a-time" behavior of IDE.

 

As to master/slave, I have always preferred to manually set that as appropriate, unless the mobo does not support it and requires cable select (like some Dells I have encountered). It is simply "one less thing to go wrong", as the cable position and drive settings will match with no detect-and-set required by the mobo BIOS. I would set your first two drives as master on separate cables, and your third (second data drive) as slave on the same cable as your first data drive.

[mazultav]

So Ive replaced both my IDE cables with 80 connector cables, and Im still getting slow PIO like speeds. Is there any setting in the bios I should look for to remedy this. Also how do I cut and past from a terminal in order to get my syslog up here for yall to look at. thanks.

 

[mazultav]

So using hdparm, I looked at both my hard drives, the both offer various PIO, DMA and UDMA modes. I get operations not permitted errors if I try to turn on DMA using hdparm -d1 /dev/(whatever harddrive)

 

Any idea why I cant turn on DMA? and why I still have slow parity builds in the 3000 min area for a 250GB parity and 200Gb data

[limetech]

Please post a link to your motherboard specifications.