Intent log size

[Prashant Zanwar_4]

Where and how to set the intent log size. What is the recommended size for it.
Thanks and regards
Prashant

[Robert-Jan Goossens]

Hi Prashant,

If you start sam, "routine tasks", "system log files" you can add logfiles and there sizes to auto administer.

Regards,
Robert-Jan

[Dave Olker]

Hi Prashant,

If you're asking about the intent log for a VxFS (i.e. JFS) filesystem, then this can only be sized when the filesystem is created with mkfs (or SAM). The syntax is:

# mkfs -F vxfs -o logsize= ...

Recommended size depends on the usage of your filesystem and the mount options you plan on using.

According to Mark Ray, who is one of the best VxFS support guys at HP, he has never seen a VxFS intent log fill up unless you are going to use the "datainlog" parameter, which may cause the intent log to fill up quicker if the default size is used. Also, the default size of the intent log will vary depending upon the size of your filesystem.

The max size is 16MB. I typically recommend using 16MB for NFS servers, but in most cases you can use the default intent log size unless you know the default won't meet your needs.

Regards,

Dave

[Prashant Zanwar_4]

Hi,
I have a message from HPSMC software that the intent log size is less than recommended. I want to know how to see as what is configured? and how to change it? What effect it has?
Thanks
Prashant

[Dave Olker]

Is the message from HPSMC indicating the intent log for their application or for the filesystems where the application resides or reads/writes with?

Dave

[Sundar_7]

It depends on the version layout of the filesystem.

Minimum value for version 2 and 3 disk layout is 32 KB.

Minimum value for version 4 layout is 256K.

use ftyp -v option against the mount point to find out the version number of the layout.

mkfs -F vxfs -m option against the filesystem will tell you the intent logsize.

[Prashant Zanwar_4]

Hi,
I have version 3 file system layouts which have logsize someplaces 1024 and at someplaces as 1024. Is this technically okay and if required can it be changed.
Thanks and regards
Prashant

[Sundar_7]

1024 is the default intent log size for filesystems > 8 MB.

I dont believe there is a way to change the intent logsize without recreating the filesystem (not that I am aware of, anyways :-).

If you decide to recreate the filesystem, use mkfs with logsize option set to the desired value.

[Dave Olker]

Hi Prashant,

The intent log size is determined by multiplying the "logsize" value by the "bsize" value. For example, on my system:

# mkfs -m /dev/vg00/lvol4
mkfs -F vxfs -o ninode=unlimited,bsize=1024,version=4,inosize=256,logsize=1024,nolargefiles /dev/vg00/lvol4 2621440

My filesystem has a "bsize" of 1K and a "logsize" of 1K, which means my intent log will be 1MB large (1K * 1K).

The "bsize" and "logsize" values are set when the filesystem is created. Once the filesystem is built, you cannot change these values. If you need to change them, you'll have to backup your filesystem data, create a new filesystem with the new settings for either bsize or logsize, or both, and then restore your filesystem data.

Hope this helps,

Dave

[Robert-Jan Goossens]

Check this doc for some more information.

Document description: Intent log size (Journaled File System, JFS)
Document id: UNX1001053

Europe
http://www4.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062966973

US
http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000062966973

Best regards,
Robert-Jan

[Prashant Zanwar_4]

Hi,
I cannot login there? I cannot see that document.
Thanks and regards
Prashant

[Sundar_7]

You need to link your support agreement to your login before you can access these docs.

[Robert-Jan Goossens]

india.birlasoft ??

Regards,
Robert-Jan

[Prashant Zanwar_4]

Hi,
No Actually I have moved to US and working with J&J for temp? How do u know india.birlasoft?
Thanks
Prashant

[Robert-Jan Goossens]

Hi Prashant, the wonderful world of google :-), if you post your email somewhere I can help you a bit.

Best regards,
Robert-Jan
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