logical volumes under 3.3

Robert Viduya robert at shangri-la.gatech.edu
Sat Sep 15 13:07:03 AEST 1990


We got 3.3 earlier this week and I've been reading over the manuals trying
to plan an install later this month.  One of our systems has 4 780M disks
and I was thinking of combining parts of all four into one giant logical
volume and use it for user file space (one of the biggest pains in the
rear on our other systems has been balancing disk utilitization across
multiple file systems dedicated to users).  Well, as I was working out
the details, I realized that the resulting logical volume would end up
being well over 2G long.  Furthermore, we may be adding more disk in the
future and I'd like to be able to just add them to the logical volume.
What happens if it goes over 4G?  With a 32-bit int/long, we can get a
maximum of 2G (signed) or 4G (unsigned).  The 3.3 manuals say you can keep
adding disk partitions to logical partitions and doesn't mention any limits
at all.  Somehow I would be very surprised if this were true (pleasantly
surprised, but surprised nonetheless).

The man page for statfs(2) seems to indicate that it could handle a
file system that was 1024G long (using 512-byte blocks), but the man
page for stat(2) indicates that the max file size is 2G.  If this is
truely the case, I'd be satisfied; we probably aren't going to have very
many files over a gigabyte.

Has anyone who's gotten 3.3 played with this stuff yet?  Is there a limit
on how large logical volumes can be?

			robert
--
Robert Viduya					   robert at shangri-la.gatech.edu
Technical Services / Office of Information Technology
Georgia Institute of Technology					 (404) 894-6296
Atlanta, Georgia	30332-0275



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