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?
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.
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...
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."
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.
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?