WD20EARS Unraid shows "Partition format: MBR: unaligned" [SOLVED]

Why does UnRaid v4.7 show when I click on the drive from the main window ("Partition format: MBR: unaligned") that my new parity drive (inserted without doing a pre-clear since it was for a parity drive) is "unaligned".

I thought 4.7 now auto detects and will use EARS drives as "aligned" (like they are suppose to be)?  I did not set any jumpers.  Just inserted the brand new (never used) drive and set it to be the parity drive, let unraid rebuild parity.

 

Could this be the cause of my performance drop moving from a black to a green parity drive?  Should I remove it and insert a pre-cleared EARS drive I have as backup?

 

Thanks,

Why does UnRaid v4.7 show when I click on the drive from the main window ("Partition format: MBR: unaligned") that my new parity drive (inserted without doing a pre-clear since it was for a parity drive) is "unaligned".

What do you have set as the default "allignment" in your settings?  I'l going to bet it used the setting you currently have specified.  On 4.7, the default, if you did not change it, is MBR-unaligned.

 

To change it now, you can un-assign the parity drive, zero the MBR, change the setting on your "settings" page to MBR-4k-aligned, and then re-assign the parity drive letting it re-calculate parity.

 

Oh yes, one more thing... It is no less important that the parity disk be exercised and completely checked for bad sectors than a data drive.  After you initially calculate parity, be absolutely certain you perform a manual parity check.  If you do not, there is no way to know the parity drive was written correctly or any bad sectors identified.

I thought 4.7 now auto detects and will use EARS drives as "aligned" (like they are suppose to be)?  I did not set any jumpers.  Just inserted the brand new (never used) drive and set it to be the parity drive, let unraid rebuild parity.

 

Could this be the cause of my performance drop moving from a black to a green parity drive?  Should I remove it and insert a pre-cleared EARS drive I have as backup?

 

Thanks,

4.7 unRAID does not detect anything.  No version of unRAID does.  The 5.0beta5 has as its default MBR 4k-aligned, the 4.7 release has as its default MBR un-aligned.  The default alignment ONLY applies if there is not an existing MBR on the disk, otherwise unRAID will use what is already there on the disk.

Thank you Joe!

 

I did do a full manual (No Correct) check after it built the parity because I didn't do the pre-clear (likely would have anyways just to make sure as you state that the parity was created correctly).

 

I'll search how to "zero" out the MBR.

 

Question if you read this: does the preclear script auto detect? or do I need to do the same to my backup EARS drive?

 

Thanks again!

I just replaced my EARS parity drive which had a jumper with a Hitachi drive and formated it with "A" option, what should I set mine to?

 

Sorry for jumping in on this thread.

4K-aligned. All new drives should be formatted as 4K aligned including EARS with no jumper.

4K-aligned. All new drives should be formatted as 4K aligned including EARS with no jumper.

A New added to unRaid, or New as in bought in the last Year (or some time frame)?

Going forward ... The only drive that should NOT use the MBR: 4K-Aligned setting is a JUMPERED WD EARS, all other drives should use MBR: 4K-Aligned.

Going forward ... The only drive that should NOT use the MBR: 4K-Aligned setting is a JUMPERED WD EARS, all other drives should use MBR: 4K-Aligned.

 

Agreed. The EARS with jumper is the only drive that should not use the 4k-aligned setting.

 

Peter

Going forward ... The only drive that should NOT use the MBR: 4K-Aligned setting is a JUMPERED WD EARS, all other drives should use MBR: 4K-Aligned.

 

Going forward ... The only NEW drive that should NOT use the MBR: 4K-Aligned setting is a JUMPERED WD EARS, all other NEW drives should use MBR: 4K-Aligned.

 

In that case, the bolded NEW refers to "New to the array".

 

I'll search how to "zero" out the MBR.

preclear_disk.sh -z /dev/sdX

will zero the MBR.

Question if you read this: does the preclear script auto detect?

If you use the current version of the preclear_disk.sh script, it will use the setting you've elected on the "Settings" page in the absence of a command line "-a" for un-aligned, or "-A" for 4k-aligned, supplied by you when invoking it.  The command line argument overrides the default you've elected.

 

You can learn a disk's alignment by typing

fdisk -lu /dev/sdX

I'll search how to "zero" out the MBR.

preclear_disk.sh -z /dev/sdX

will zero the MBR.

Question if you read this: does the preclear script auto detect?

If you use the current version of the preclear_disk.sh script, it will use the setting you've elected on the "Settings" page in the absence of a command line "-a" for un-aligned, or "-A" for 4k-aligned, supplied by you when invoking it.  The command line argument overrides the default you've elected.

 

You can learn a disk's alignment by typing

fdisk -lu /dev/sdX

 

I used preclear_disk.sh v.1.7 to preclear the other drive on 5.0-beta5 (which defaults to 4k-aligned - i checked and it is set to that) yet the brand new never used drive was unaligned when I added it to my UnRaid 4.7 production machine.

 

Good news is that my performance jumped +10MB/s having the EARS parity drive 4k-aligned (no jumper)

Thanks Joe and everyone else who answer! Your time and advise are GREATLY appreciated!

 

I just added a new drive (hitachi 5k3000) and I didn't do the 4k align formatting. What is the significance in doing this? performance increase?

I just added a new drive (hitachi 5k3000) and I didn't do the 4k align formatting. What is the significance in doing this? performance increase?

 

Not sure if that is an Advanced Format Drive... But I know that with my WD20EARS drive (which is an AF drive), with NO JUMPER, you have to do the 4k-align or there is a huge performance penalty (~ 10MB/s less when formatted "unaligned").

I just added a new drive (hitachi 5k3000) and I didn't do the 4k align formatting. What is the significance in doing this? performance increase?

No impact at all, other than it is compatible with older versions of unRAID, whereas those partitioned to start at sector 64 are not.

 

Only  "Advanced Format" drives with internal 4k sectors will be impacted if not accessed on a 4k boundary.  All other drives expect to be accessed on a 512 byte boundary.  Your non-AF drive will work just fine regardless of how it is partitioned.

I don't believe Hitachi says any of their drives are Advanced Format, but it would really surprize me if their 3T drive lines don't use 4k sectors.

 

Once again, the best option is to just use 4k-aligned for EVERY SINGLE drive and do not install jumpers on any new EARS drive.

 

Drives that are not advanced format DO NOT need to use the unaligned setting. 4k-aligned works just as well for them.

 

Peter

And if the jumper is in place then it too does NOT care.  This setting only comes into play when a new un-jumpered EARS drive is added, all old and EARS with jumper remain un-changed or affected right?

And if the jumper is in place then it too does now care.  This setting only comes into play when a new un-jumpered EARS drive is added, all old and EARS with jumper remain un-changed or affected right?

 

Yes.

And if the jumper is in place then it too does NOT care.

 

I'm not clear exactly what you mean by this statement but, just to clarify, an EARS drive with jumper installed will suffer from degraded performance if the partition is 'aligned'.

so i understand that the ears with jumpers is ok for it to be unaligned but i have an EADS that im trying to align that has NO jumper i tried the preclear_disk.sh -z /dev/sdX and it didnt work i get back "-bash: preclear_disk.sh: command not found" and yes i changed the X to the appropriate drive

EADS are not advanced format so either way works with them.

 

You have to cd to the directory where the script is. "cd /boot" will get you to the root of the flash drive which is likely where you put it.

 

Peter

 

ah i see ha ima tard sorry i will try that once i get another problem corrected..lol...is it just cd boot or cd flash boot? its named flash

No, it's only named flash over the network. It's named boot on the server. The flash is at /boot so use cd /boot. If you "cd boot" when you login then you won't get there either. You have to first cd to the top of the filesystem where the boot directory is before cd boot would work.

 

Peter

sounds good thanks again sir!

so still not working for me. but you say EADS is not advanced format so does that mean if i get the MBR to be aligned it wont make a difference in performance? if it wont impact performance do you see any reason to get this corrected for in the future?

 

i got to my boot dir root@tower:/boot# and i tried using preclear_disk.sh -z /dev/sdX still says command not found???

 

If you tell me no difference in performance i will give up if can slightly help i will try to fix it (;