Filesets in Filesystems in relation to Checkpoint

[Jbert]

What are filesets in a filesystems and how are they connected to Filesystem Checkpoint. I read there are two types of Filesets. why? What the two types Store/point-to?

[Gaurav_S]

There are certainly 2 types of filesets.... I remember one is fileset 999 ..... not able to reckon other....
 
you can check the same on your filesystem using "ncheck" command.... check man page of ncheck for more help...

I don't believe they would have hard connection to filesystem checkpoints.... majorly filesets display inode related information.... for e.g which inode contain which files at which fileset...

Gaurav

[g_lee]

The following link may be helpful:
http://forums13.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1280141794868+28353475&threadId=661198

The last comment (Chris Shoesmith's) in particular might be of interest (extracts quoted below)

"fileset 999 (UNNAMED fset) contains the information pertinent to the user files in a vxfs filesystem. Fileset 1 is the ATTRIBUTE Fset containing much of the non-filedata extents and objects, think of it as a management Fileset. Some objects in the FSET 1 actually point to objects in FSET999. So these can't be considered totally seperate.

[....]

You might also see fset 1000+ in newer filesystem versions, where these are checkpoints."

[avsrini · Accepted solution]

Hi Jbert,

 In a simple term, filesets in VxFS are just a sets of metada or control data of the filesystem.
fileset 1 = metadata for the metada of userdata
fileset 999 = metadata of the user data
fileset 1000+ = metadata for first and rest of the filesystem checkpoints.

Pls note filesystem checkpoints are point in time copy of user data.

Regards
Srini

[Jbert]

That means whenever a chekpoint is created, the fileset 999 is copied, and a link is created to fileset 1 but not copied, and these info go in fileset 1000 for the checkpoint. And that there is a link from fileset 999 to the fileset 1000 so that it can be found and the data updated to it. Am i right?

[Gaurav_S]

sounds fair statement....