"MBR: unaligned" format on both WD EARS Advanced Format HDDs


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I can't seem to be able to find the answer to my worry on the forums so I'll ask this question and hope someone can provide a confirmation.

 

Setup:

 

Brand-new unraid 4.7 Server Basic

2 2TB WDC_WD20EARS Advanced Format HDD's (1 parity 1 data)

 

After an overnight parity-sync, the array has all green lights.  Then I noticed that both drives have "MBR: unaligned" formats. I read

http://www.lime-technology.com/wiki/index.php?title=Advanced_Format_Drives and

http://lime-technology.com/forum/index.php?topic=9936.0

that unRaid 4.7 natively supports these Advanced Format drives.  Yet on

http://lime-technology.com/forum/index.php?topic=11544.0

the last poster mentioned that "the best option is to just use 4k-aligned for EVERY SINGLE drive and do not install jumpers on any new EARS drive".

 

Should I worry about my array that has both drives in "MBR: unaligned" format?

 

Thanks in advance for your help.

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The short answer is yes. there is a preformance hit on ears with no jumpers if they are not alined.

but if they do have a jumper then they work correctly, or if there is no jumper and are not alinged.

 

causion if you just install the jumper... it will need to be reformated and will loose all data.

 

if there jumper is not installed, then just move your data off the data drive and use preclear with the -A option. once done do the same for parity drive.

 

in the setings page set the default to alinged for future drives. and you are done.

 

hope this helps.

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It sounds like your array is new and empty. If you did not install jumpers then do the following;

 

Download the precelar script and run the command;

 

preclear_disk.sh -z /dev/sdX

 

or

 

Type this command in unRAID;

 

dd if=/dev/zero count=8 of=/dev/sdX

 

 

Do the above for every EARS drive without a jumper. The sdX respresents the drive identifier you will see on the devices page, such as (sda or sdb).

 

Peter

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Thanks Thornwood for the quick response.  My HDDs are straight from vendor without any mod (therefore no jumper).

 

Sounds like I should re-do the array from scratch to re-gain the performance hit.  I did notice a less-than-expected disk performance (max'ed out around 30MB/s total doing a from-Windows file copy).

 

Do I absolutely have to do a preclear_disk.sh on each HDD?  I gave it a try but it took 15hours or so for one of my 2TB.  Can I just do an initconfig on the shell and re-create the array from scratch?  What's the drawback if I skip the preclear_disk?

 

 

The short answer is yes. there is a preformance hit on ears with no jumpers if they are not alined.

but if they do have a jumper then they work correctly, or if there is no jumper and are not alinged.

 

causion if you just install the jumper... it will need to be reformated and will loose all data.

 

if there jumper is not installed, then just move your data off the data drive and use preclear with the -A option. once done do the same for parity drive.

 

in the setings page set the default to alinged for future drives. and you are done.

 

hope this helps.

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Ok I did the preclear_disk.sh -z on both HDDs, changed Default partition format to "MBR: 4K aligned" under settings on the unraid GUI, then brought back the array.  There are green lights beside the drives and things look normal.  Both drives have "Partition format: unknown" now, so I don't think I've changed anything with respect to the format of the drives.  Was it all I needed to change the format of the drives?

 

It sounds like your array is new and empty. If you did not install jumpers then do the following;

 

Download the precelar script and run the command;

 

preclear_disk.sh -z /dev/sdX

 

or

 

Type this command in unRAID;

 

dd if=/dev/zero count=8 of=/dev/sdX

 

 

Do the above for every EARS drive without a jumper. The sdX respresents the drive identifier you will see on the devices page, such as (sda or sdb).

 

Peter

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Ok I did the preclear_disk.sh -z on both HDDs, changed Default partition format to "MBR: 4K aligned" under settings on the unraid GUI, then brought back the array.  There are green lights beside the drives and things look normal.  Both drives have "Partition format: unknown" now, so I don't think I've changed anything with respect to the format of the drives.  Was it all I needed to change the format of the drives?

 

 

You started the array and they show as "unknown"? Something isn't right if it shows as unknown. A "green" drive should be partitioned either unaligned or 4k aligned. Try stopping, unassigning both drives, then assigning them again. You may have to do the initconfig to get it started again. You should have to format the data drive and build parity again.

 

Peter

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Ok I am following this http://www.lime-technology.com/wiki/index.php?title=Advanced_Format_Drives, stopped the array, unassigned disk1, restarted and stopped the array, re-assigned disk1, started the array, and it's now doing data-rebuild.  Disk1 shows "MBR: 4K-aligned" now!

 

I'll repeat this process for the parity disk.  Hopefully in 24hrs I can report a successful result.

 

Thanks for your help Peter.

 

 

You started the array and they show as "unknown"? Something isn't right if it shows as unknown. A "green" drive should be partitioned either unaligned or 4k aligned. Try stopping, unassigning both drives, then assigning them again. You may have to do the initconfig to get it started again. You should have to format the data drive and build parity again.

 

Peter

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I'm happy to report that both the data and parity disks are rebuilt successfully.  Now both are in MBR: 4K Aligned format.

 

I'm really surprised that this whole operation ran without any loss of data, and the data could be accessed at the same time.

 

Thanks to Peter for your help.

 

 

 

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I'm a little surprized about that too actually. You said the array was brand new and I figured disk1 would be formatted back to empty when you cleared the MBR of both the parity and disk1 at the same time (since this is like having 2 disks fail at the same time). I'm not really sure how a disk with an "unknown" partition was considered valid but it accepted them for some reason.

 

Peter

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After I created the array I installed Transmission and downloaded a file.  During the rebuild/reformat process Transmission was running fine after a re-check.  Also, I moved 125GB of home videos to unRaid (that's the major reason why I built the box!).  Things are fine during and after the rebuilding of the 2 drives.

 

Some other experts on "AF drives wth no jumper + unraid 4.7" might be able to explain why your method of clearing the MBR by "preclear_disk.sh -z /dev/sd*" preserves the data during a reformat/rebuild.

 

I'm a little surprized about that too actually. You said the array was brand new and I figured disk1 would be formatted back to empty when you cleared the MBR of both the parity and disk1 at the same time (since this is like having 2 disks fail at the same time). I'm not really sure how a disk with an "unknown" partition was considered valid but it accepted them for some reason.

 

Peter

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