Can my parity disk be the same size as the data disks?

[jgray]

I have 3 250GB disks (all the same model) and when I set one of them as the parity it thinks it is 1K smaller than the other 2.  Can my parity be the same disk size as the others?

[smeehrrr]

Different "250GB" disks from different manufacturers can vary by a few blocks either way.  You have to pick the largest 250GB disk as your parity drive.

 

[jgray]

All 3 are the same manufacturer and model, when I change them around the same thing seemed to happen.  I suspect it is how the software formats the parity disk but would like confirmation.

[teamhood]

I have 3 250GB disks (all the same model) and when I set one of them as the parity it thinks it is 1K smaller than the other 2.  Can my parity be the same disk size as the others?

 

Wow... that is really, really annoying!! I have 3 different 400GB hard drives from different manufactures in my array and I have no run into this problem. They all show up exactly the same size! Might have to wait for Tom to come around and advise. I am still waiting for him to respond to my annoying problem with the array... but it sounds like he it really working on finishing the new releases.

[Suse User]

If you read my thread http://lime-technology.com/forum/index.php?topic=125.0, I had the same problem as you.

 

Turned out that despite the fact I had 3 brand new identical 400gb drives one of them is showing as being 1056bytes smaller than the others.  What I was mistaking as a system board error was unraid warning me.

 

3 Identical 400gb Drives, but whichever was in the parity slot was detected as slightly smaller.  In the end I had to given each a turn at being the parity drive to make them all the same size in UnRaid.  It was long winded and not something I wish to repeat and is what's stopping me upgrading to bigger drives again.

 

I hope this gets sorted as I thought I was the only person to have experienced this.

 

Good luck!

[jgray]

1056 bytes exactly the same as my issue. 

UnRaid Support, any chance of a fix for this?

[limetech]

jgray & suse user,

 

Could you each tell me the "history" of your drives?  That is, I'm wondering if some or all started out life in another linux system and then you used them to poplulate your unRAID server?  If so, which distro?

 

I have a "hunch" why this is happening, but I can't exactly reproduce the 1056 difference (have reproduced other values though).

[Suse User]

jgray & suse user,

 

Could you each tell me the "history" of your drives?  That is, I'm wondering if some or all started out life in another linux system and then you used them to poplulate your unRAID server?  If so, which distro?

 

All 3 Shiny new drives here, bought at the same time with very similar serial numbers.  I did already have another 400gb drive of the same make & model installed.

[limetech]

So how did you finally resolve the issue?  Can you send me the Model number and size currently being displayed for these drives in the Management Utility? 

[Suse User]

So how did you finally resolve the issue?  Can you send me the Model number and size currently being displayed for these drives in the Management Utility? 

 

All 3 Drives are Seagate ST3400832A, I actually have 4 of these drives, I had one already that had been Reiserfs formatted under Suse 9.1 before my server was running UnRaid.

 

The older (few months older) one was showing a size of 390,711,352.  I introduced the 3 new drives, one into parity and 2 other bare drives and re-built parity.  All was ok until I had to power off where after a reboot the array wouldn't come up stating that the Parity drive was too small.  Checking the status page I could see that my parity drive now had a size of 390,710,296.

 

I followed some instructions from Joe to remove all data & formatting from the new drives (see my thread mentioned earlier), swapped the parity with Disk1 and rebuilt parity again.  Again all ok until a reboot then...

Notice that the parity drive is again reduced, but also the previous parity drive (now drive 1) has remained at the smaller size.

 

I had to follow the same procedure giving each of my 4 x 400gb drives a turn at being parity and I eventually ended up with all 4 at the slightly smaller size.

 

I hope this helps,

 

Mark.

[jgray]

Mine also were 3 brand new drives (Hitachi HDT722525DLAT80)

I did the same thing and rebuilt parity on different drives in my case the 3rd one stayed the larger size.

[Suse User]

Mine also were 3 brand new drives (Hitachi HDT722525DLAT80)

I did the same thing and rebuilt parity on different drives in my case the 3rd one stayed the larger size.

 

Have you switched off your server since the last time?  Mine only appeared smaller after a reboot.

 

Mark.

[limetech]

Did the shrinkage only occur with the drive in the parity slot??

[Suse User]

Did the shrinkage only occur with the drive in the parity slot??

From my understanding of what happened...Yes.

[Rascal]

I have exactly the same problem. Installed three fresh seagate 250GB drives everything was fine until I rebooted and the parity disk is now smaller than the other 3.

 

Model/Serial No. Temperature Size Free Reads Writes Errors

parity ST3250820A/5QE0R1XC

ST3250820A/5QE0R1XC * 244,197,496

244198552 - - - -

disk1 ST3250820A/5QF0EQJE * 244,198,552 - - - -

disk2 ST3250820A/5QF0B1ER * 244,198,552 - - - -

 

[limetech]

We're going to purchase a set of those drives and see if we can reproduce this problem.  You'll notice the size is different by 1056 (as in previous cases), which is 1024+32, which you'd think we could find a bug for, but believe me, a lot of time has been spent without an answer to this problem.

[Rascal]

I swapped my parity disk with one of the data disks then rebuilt the parity. This time around the new parity hasn't shrunk and it all appears to be okay.

 

The previous parity disk is now formatted and still 1056 bytes smaller than the others. Odd.

 

Anyway looks like I am up and running and ready to start storing data 

[Suse User]

I swapped my parity disk with one of the data disks then rebuilt the parity. This time around the new parity hasn't shrunk and it all appears to be okay.

 

The previous parity disk is now formatted and still 1056 bytes smaller than the others. Odd.

 

Anyway looks like I am up and running and ready to start storing data 

You may wish to consider giving the 3rd drive a turn at being Parity just to make sure.  I had terrible trouble trying to find temporary storage for my files when my problem reoccurred after I had populated my array.

 

Just a suggestion

 

Mark.

[Rascal]

Hi Mark, Are you saying that your parity disk shrunk at a later date once you started adding data ?

 

I may just go buy a bigger disk to avoid this.

[Suse User]

Hi Mark, Are you saying that your parity disk shrunk at a later date once you started adding data ?

 

I may just go buy a bigger disk to avoid this.

Yes, it did, but I'm unsure whether I had actually powered off between creating the 2nd Parity disk and populating the other 2, I thought I had a problem with a specific disk, it was not until the 2nd time it happened I was aware there was a pattern to it.  If it was me, for my peace of mind I'd make sure all HDDs that I'd bought are reading the same size under unraid before populating up the array.

 

I want to switch to some bigger drives myself, but my experiences last time are making me put off any upgrades until this problem has been nailed.

 

Mark.