Hi Aran,

Nope, normal format...

But the disk is 1 Gigabyte in size (part of a 5 disk R5 set)...

The format under W2k3 would be done in no time at all (Normal format) whilst in W2k8 it takes almost a minute!

Fred

Hi All,

The quick format is indeed quick, but I wonder why a normal format is so much more slower compared to a normal format in Windows 2003?

I seem to recall a specific EMC document on LUN alignment within Windows 2008

I even think I saw it in these fora

Anybody from EMC know of this document/whitepaper on LUN Alignmnet on W2k8???

Fred

Hi Glen,

Thanks for your answer and the document, but:

1) I guess it doesn't matter, but we have a CX3-80 with Release 26 (.16)

2) Does that remark on page 22 mean I do not need to align the storage in 2008 server myself anymore, as Windows 2008 server offsets the partition itself???

3) If indeed alignment in Windows 2008 server is not needed anymore: I actually did execute the DISKPART command 'create partition primary align=64'. How does this mix with the OS doing its own alignment???

4) Should I get rid of the partition (And my manual alignment) and reformat, thus letting Windows 2008 server do its own alignment?

Thanks for the information! Very informative

Fred

Hi Aran,

Very interesting

Here is the info of my server:

wmic partition get BlockSize, StartingOffset, Name, Index

BlockSize Index Name StartingOffset
512 0 Disk #0, Partition #0 32256
512 1 Disk #0, Partition #1 41943040
512 2 Disk #0, Partition #2 52470743040
512 0 Disk #8, Partition #0 65536
512 0 Disk #7, Partition #0 65536
512 0 Disk #10, Partition #0 1048576

Disk #0 is a local (non san) disk with 3 partitions

Disk #7 and #8 are my SAN disks and are indeed aligned to my DISKPART command (Create partition primary Align=64)

To test, I've also added disk #10 and didn't do any alignment and let Windows decide it for itself.

What is strange is:

Disk #0 32256/512 = 63 sectors offset
Disk #7 & Disk #8 655336/512 = 128 sectors offset
Disk #10 1048576/512 = 2048 sectors offset

For disk #0 it was able to decide for itself... Why has it chosen that offset?!?

Also:

Will you stop aligning yourself in Windows 2008 now?

Thanks!

Fred

...Until we hear that 1MB is really a poor alignment...

Indeed

I've been checking my 'super aligned' disks in NaviSphere:

I've disabled (and re-enabled) Statistics Logging on the SANs to reset the Statistics Counters in the LUN details...

I still see enourmous numbers of 'Stripe Crossings' when I put some heavy I/O to the aligned disk (I started a defragmentation)...

How on earth is one to decide whether or not it is optimally configured?!?

Fred

Hi Glen,

In Navisphere whilst viewing the PROPERTIES of a particular LUN.

One of the tabs is called STATISTICS and contains (among other fields) the field NUMBER OF STRIPE CROSSING

Fred

Fred,
I just tested this again on a Windows 2008 x64 cluster. Not using Quick Format on a 15GB LUN took a few minutes. Using Quick Format on the same LUN took only a few seconds.

Aran

Try it with quick format and see if that helps. I remember reading an article a long time ago that said to use quick format for SAN based LUNs in Windows for some reason that I forget...

Using quick format in Windows 2008 x64 and x86 I have not had any LUN format take longer than a few seconds.

Fred,
The LUN alignment is the same. Silly question, but did you select Quick Format?

I though I saw a Microsoft document that says you don't need to offset disks in Windows 2008 - that all disks when initialized in Windows the offset is set to 1 MB.

glen