Solaris

So what can be done in current scenario. Do u think it can be extended? If yes then How?
Please explain as i m curious to know if there is any other way of increasing root partition.

Yes although you need the "-o largefiles" mount option set.

---------- Post updated at 12:57 ---------- Previous update was at 12:38 ----------

Knowing the precise slice layout (vtoc) is a requirement to know if the root partition then the file system inside it can be expanded.

confused i think i need to learn more about vtoc.

and i disagree with you. if a drive is fully used (and we don't know the drive layout) you can't resize a partion, even if you use some sort of volumemanagement (unless you shrink another partition).
everything is said allready:
1. we need the drivelayout (vtoc -> "prtvtoc /dev/dsk/c0t0d0s2)
2. is some kind of volumemanagement used?
3. from a guess i think we are talking about a solaris 6 system; so lots of the modern tools are missing (liveupgrade; flasharchive)
4. growing and shrinking filesystems is always a problematic thing to do; one error during the procedure and your data might be lost!

so, the working conclusion with an external /opt slice is a good solution in this case, isn't it?
if there is a chance to use a second drive (maybe a bigger one) you can saftly do a ufsdump/ufsrestore for every slice on the old disk to the knew one while bootet from cd/net. this is, in my opinion, the safest solution for this kind of problem...