!!!URGENT!!! Disk format slow in Windows 2008 server

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

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

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

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

For Windows 2008 see page 22 at top of page - "Microsoft-based File-system Alignment Procedure"

EMC CLARiiON Performance and Availability Release 28.5 Firmware Update Applied Best Practices.pdf

http://powerlink.emc.com/km/live1/en_US/Offering_Technical/White_Paper/h5773-clariion-perf-availability-release-28-firmware-wp.pdf

glen

This is correct. I just tested it on a Windows 2008 server. Creating the partition without specifying the offset resulted in a partition with a 2048 sector offset, or 1MB.

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

The information in release 28 still applies mostly to release 26.

Windows 2008 does set the offset - see note above from AranH

As to fixing, I guess you could run the diskpart using the value that AranH saw, or you could start over (unbind LUN, create new LUN). Leaving it at 64 should be OK as it is an offset that aligns the file-system. Seems that Microsoft just made it bigger just to be sure.

If you already have data on the LUN, then you can't redo without losing all data.

glen

I have been using the "align=64" option on Windows 2008 up to now and it does create the alignment properly as specified and is still aligned properly at 64KB, just not at the new Windows default of 1024KB.

Run the following command from a command prompt:
wmic partition get BlockSize, StartingOffset, Name, Index

Divide the Offset by the Block Size and you will have your offset in sectors.

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

The boot/system volume partition is still created through the OS install process the same way as previous versions Windows, with the 63 sector offset. Not sure why the didn't change that

Yes, now that I have been enlightened I will stop manually aligning new volumes on Windows 2008. Until we hear that 1MB is really a poor alignment choice for SAN based LUNs and that we should all go back to 64K

...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

Well stripe crossings are normal if you are writing data that is larger than the stripe for your LUN. So that is not an indication of a performance issue or misalignment. So looking at that counter to determine LUN performance is not an accurate view of performance.

A couple of documents for you if you have not read them already are below. These documents provide some good guidelines to ensure that your configurations are optimized for the performance you require.

EMC CLARiiON Best Practices For Performance and Availability: Release 28.5 Firmware Update ¿ Applied Best Practices
Home > Products > Hardware/Platforms > CLARiiON > CLARiiON CX4 Series > White Papers

EMC CLARiiON Best Practices for Fibre Channel Storage: FLARE Release 26 Firmware Update - Best Practices Planning
Home > Products > Hardware/Platforms > CLARiiON > CLARiiON CX3-40 > White Papers