SUMMARY: ufsdump to file, 2Gb limit?

Ron Stanonik (
Wed, 15 Oct 1997 14:21:54 +0800

The question was:

Normally we use ufsdump to backup our filesystems to Exabyte drives.
Recently we needed a quick backup and decided to backup to a file
in a large, empty filesystem. We used the same parameters as for
an Exabyte drive, replacing the tape drive with the backup file:

ufsdump 0dsbf 54000 26000 126 /usr4/home0.dump /home0

The backup failed with

cedar# ufsdump 0dsbf 54000 26000 126 home0.dump /home0
DUMP: Writing 63 Kilobyte records
DUMP: Date of this level 0 dump: Tue Oct 14 17:45:11 1997
DUMP: Date of last level 0 dump: the epoch
DUMP: Dumping /dev/vx/rdsk/rootdg/vol03 (cedar:/home0) to home0.dump
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 8719376 blocks (4257.51MB) on 0.53 tapes.
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 12.48% done, finished in 1:13
DUMP: 25.98% done, finished in 0:58
DUMP: 39.48% done, finished in 0:46
DUMP: Write error 1531248 blocks into volume 1
DUMP: NEEDS ATTENTION: Do you want to restart?: ("yes" or "no")

The answer is:
Solaris 2.5 limits filesize to 2GB; ie, home0.dump ran into the
filesize limit. I confused the filesystem limit with the filesize
limit. Solaris 2.6 raises the filesize limit.

Thanks to: (Marc S. Gibian) (Craig Gates)
"Bruce Rossiter" <> (Darryl Levesque) (Alfred Moscola)
Sean Ward <>
leach@OCE.ORST.EDU (Tom Leach) (Charles Seeger)
Eugene Kramer <> (Charles Seeger)
Mike Blandford <>
Jim Harmon <>

Thanks also for some suggestions to work around the limit:

From: leach@OCE.ORST.EDU (Tom Leach)
Subject: Re: ufsdump to file, 2Gb limit?

Ron, until Solaris 2.6, there is a max file size (not filesystem size) of
2GB. One work around would be to didle the length and density settings to
be just under 2 GB, then when the backup asks for the second (and third)
tapes, you just moved home0.dump to home0.1.dump, (followed by
home0.2.dump and home0.3.dump). Bit of a pain, but at least it's doable.
Tom Leach

From: (Charles Seeger)
Subject: Re: ufsdump to file, 2Gb limit?

| Does ufsdump have a 2GB limit when dumping to a file? Anyway around it?

Ah, forgot to answer this part. Assuming that you are not massively
exceeding 2GB, you could pipe the dump output through crompress or
gzip. As long as the total compressed size was under 2GB you should
be OK. I'm not sure about restore though. If you are extracting the
entire tape you should be able to zcat into restore. Alternatively,
you could zcat into dd and send it to a device that supports larger
files (e.g. a tape drive) and restore normally. I would be interested
to hear if "zcat <dumpfile> | restore if -" works.

Charles Seeger <>