DUMP: short read error from
ronen amity
the disk is mirrord, and tar to /dev/null works fine.
I get this log :
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 /dev/dsk/c0t0d0s0
Mon Nov 5 23:30:46 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:30:46 2001
DUMP: Date of last level 0 dump: Sun Nov 04 23:30:44 2001
DUMP: Dumping /dev/rdsk/c0t0d0s0 (police:/) to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 610 blocks (305KB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 510 blocks (255KB) on 1 volume at 118 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:30:46 2001
Mon Nov 5 23:30:57 EET 2001
Mon Nov 5 23:30:57 EET 2001
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 /dev/dsk/c0t0d0s4
Mon Nov 5 23:30:57 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:31:00 2001
DUMP: Date of last level 0 dump: Sun Nov 04 23:31:28 2001
DUMP: Dumping /dev/rdsk/c0t0d0s4 (police:/usr) to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 958 blocks (479KB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 766 blocks (383KB) on 1 volume at 356 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:31:00 2001
Mon Nov 5 23:31:24 EET 2001
Mon Nov 5 23:31:24 EET 2001
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 /dev/dsk/c0t0d0s5
Mon Nov 5 23:31:24 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:31:25 2001
DUMP: Date of last level 0 dump: Sun Nov 04 23:40:57 2001
DUMP: Dumping /dev/rdsk/c0t0d0s5 (police:/var) to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 34608 blocks (16.90MB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 34558 blocks (16.87MB) on 1 volume at 2536 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:31:25 2001
Mon Nov 5 23:31:41 EET 2001
Mon Nov 5 23:31:41 EET 2001
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 //dev/dsk/c0t0d0s3
Mon Nov 5 23:31:41 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:31:42 2001
DUMP: Date of last level 0 dump: Sun Nov 04 23:42:13 2001
DUMP: Dumping /dev/rdsk/c0t0d0s3 to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 458 blocks (229KB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 254 blocks (127KB) on 1 volume at 192 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:31:42 2001
Mon Nov 5 23:31:46 EET 2001
Mon Nov 5 23:31:46 EET 2001
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 /dev/md/dsk/d2
Mon Nov 5 23:31:46 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:31:47 2001
DUMP: Date of last level 0 dump: Sun Nov 04 23:44:16 2001
DUMP: Dumping /dev/md/rdsk/d2 (police:/usr/mwdata) to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 159196 blocks (77.73MB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 159230 blocks (77.75MB) on 1 volume at 3178 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:31:47 2001
Mon Nov 5 23:34:21 EET 2001
Mon Nov 5 23:34:21 EET 2001
spawn /usr/sbin/ufsdump 2ufb /dev/rmt/0cn 256 /dev/md/dsk/d3
Mon Nov 5 23:34:21 EET 2001
DUMP: Writing 128 Kilobyte records
DUMP: Date of this level 2 dump: Mon Nov 05 23:34:21 2001
DUMP: Date of last level 0 dump: Mon Nov 05 00:39:19 2001
DUMP: Dumping /dev/md/rdsk/d3 (police:/usr/staff) to /dev/rmt/0cn.
DUMP: Mapping (Pass I) [regular files]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Mapping (Pass II) [directories]
DUMP: Estimated 920790 blocks (449.60MB).
DUMP: Dumping (Pass III) [directories]
DUMP: Dumping (Pass IV) [regular files]
DUMP: 918782 blocks (448.62MB) on 1 volume at 2552 KB/sec
DUMP: DUMP IS DONE
DUMP: Level 2 dump on Mon Nov 05 23:34:21 2001
Mon Nov 5 23:45:01 EET 2001
Mon Nov 5 23:45:01 EET 2001
Mon Nov 5 23:45:01 EET 2001
mt off
chs deselect -d 1 -s 6
dump lvl is: 2
spawn /sbin/dump 2ufbds guesttp@police:/dev/rmt/0cn 64 45000 54000 /dev/sda1
Mon Nov 5 23:47:22 GMT-2 2001
DUMP: Connection to police established.
DUMP: Date of this level 2 dump: Mon Nov 5 23:47:22 2001
DUMP: Date of last level 0 dump: Mon Nov 5 03:22:55 2001
DUMP: Dumping /dev/sda1 (/) to /dev/rmt/0cn on host guesttp@police
DUMP: Label: none
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 159 tape blocks on 0.00 tape(s).
DUMP: Volume 1 started at: Mon Nov 5 23:47:27 2001
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /dev/rmt/0cn
DUMP: Volume 1 completed at: Mon Nov 5 23:47:32 2001
DUMP: Volume 1 took 0:00:05
DUMP: Volume 1 transfer rate: 48 KB/s
DUMP: DUMP: 243 tape blocks on 1 volumes(s)
DUMP: finished in less than a second
DUMP: level 2 dump on Mon Nov 5 23:47:22 2001
DUMP: DUMP: Date of this level 2 dump: Mon Nov 5 23:47:22 2001
DUMP: DUMP: Date this dump completed: Mon Nov 5 23:47:32 2001
DUMP: DUMP: Average transfer rate: 48 KB/s
DUMP: DUMP IS DONE
Mon Nov 5 23:47:32 GMT-2 2001
Mon Nov 5 23:47:32 GMT-2 2001
spawn /sbin/dump 2ufbds guesttp@police:/dev/rmt/0cn 64 45000 54000 /dev/sda5
Mon Nov 5 23:47:32 GMT-2 2001
DUMP: Connection to police established.
DUMP: Date of this level 2 dump: Mon Nov 5 23:47:32 2001
DUMP: Date of last level 0 dump: Mon Nov 5 03:24:08 2001
DUMP: Dumping /dev/sda5 (/usr) to /dev/rmt/0cn on host guesttp@police
DUMP: Label: none
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 63106 tape blocks on 0.00 tape(s).
DUMP: Volume 1 started at: Mon Nov 5 23:47:48 2001
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /dev/rmt/0cn
DUMP: Volume 1 completed at: Mon Nov 5 23:48:10 2001
DUMP: Volume 1 took 0:00:22
DUMP: Volume 1 transfer rate: 2869 KB/s
DUMP: DUMP: 63120 tape blocks on 1 volumes(s)
DUMP: finished in 22 seconds, throughput 2869 KBytes/sec
DUMP: level 2 dump on Mon Nov 5 23:47:32 2001
DUMP: DUMP: Date of this level 2 dump: Mon Nov 5 23:47:32 2001
DUMP: DUMP: Date this dump completed: Mon Nov 5 23:48:10 2001
DUMP: DUMP: Average transfer rate: 2869 KB/s
DUMP: DUMP IS DONE
Mon Nov 5 23:48:10 GMT-2 2001
Mon Nov 5 23:48:10 GMT-2 2001
spawn /sbin/dump 2ufbds guesttp@police:/dev/rmt/0cn 64 45000 54000 /dev/sdd5
Mon Nov 5 23:48:10 GMT-2 2001
DUMP: Connection to police established.
DUMP: Date of this level 2 dump: Mon Nov 5 23:48:10 2001
DUMP: Date of last level 0 dump: Mon Nov 5 03:32:54 2001
DUMP: Dumping /dev/sdd5 (/var) to /dev/rmt/0cn on host guesttp@police
DUMP: Label: none
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 91921 tape blocks on 0.00 tape(s).
DUMP: Volume 1 started at: Mon Nov 5 23:48:13 2001
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: Closing /dev/rmt/0cn
DUMP: Volume 1 completed at: Mon Nov 5 23:49:16 2001
DUMP: Volume 1 took 0:01:03
DUMP: Volume 1 transfer rate: 1456 KB/s
DUMP: DUMP: 91789 tape blocks on 1 volumes(s)
DUMP: finished in 62 seconds, throughput 1480 KBytes/sec
DUMP: level 2 dump on Mon Nov 5 23:48:10 2001
DUMP: DUMP: Date of this level 2 dump: Mon Nov 5 23:48:10 2001
DUMP: DUMP: Date this dump completed: Mon Nov 5 23:49:16 2001
DUMP: DUMP: Average transfer rate: 1456 KB/s
DUMP: DUMP IS DONE
Mon Nov 5 23:49:16 GMT-2 2001
Mon Nov 5 23:49:16 GMT-2 2001
spawn /sbin/dump 2ufbds guesttp@police:/dev/rmt/0cn 64 45000 54000 /dev/md1
Mon Nov 5 23:49:16 GMT-2 2001
DUMP: Connection to police established.
DUMP: Date of this level 2 dump: Mon Nov 5 23:49:16 2001
DUMP: Date of last level 0 dump: Mon Oct 29 03:45:13 2001
DUMP: Dumping /dev/md1 (/var/spool/imap) to /dev/rmt/0cn on host
guesttp@police
DUMP: Label: none
DUMP: mapping (Pass I) [regular files]
DUMP: mapping (Pass II) [directories]
DUMP: estimated 1262483 tape blocks on 0.07 tape(s).
DUMP: Volume 1 started at: Mon Nov 5 23:50:39 2001
DUMP: dumping (Pass III) [directories]
DUMP: dumping (Pass IV) [regular files]
DUMP: 47.20% done, finished in 0:05
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -1686942968]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942968]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942967]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942966]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942965]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942964]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942963]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942962]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686942961]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -1847521024]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521024]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521023]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521022]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521021]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521020]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521019]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521018]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1847521017]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -1572204104]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204104]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204103]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204102]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: DUMP: bread: lseek fails
bread: lseek2 fails!
DUMP: DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -1572204104]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204104]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204103]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204102]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204101]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204100]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204099]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204098]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204097]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
short read error from /dev/md1: [sector -1572204101]: count=512, got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204100]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204099]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204098]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1572204097]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -1686414880]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414880]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414879]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414878]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414877]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414876]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414875]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414874]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -1686414873]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -513674392]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674392]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674391]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674390]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674389]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674388]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674387]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674386]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674385]: count=512,
got=0
DUMP: bread: lseek fails
DUMP: short read error from /dev/md1: [block -513674392]: count=4096,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674392]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674391]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674390]: count=512,
got=0
DUMP: bread: lseeexpect: invalid spawn id (6)
while executing
"expect -nobrace "Is the new volume mounted and ready to go" {
take_from_tape $tapedevice $curr_tape
incr curr_tape 1
sleep 30
put_in_ta..."
invoked from within
"expect {
"Is the new volume mounted and ready to go" {
take_from_tape $tapedevice $curr_tape
incr curr_tape 1
sleep 30
put_in_tape $tape..."
("while" body line 2)
invoked from within
"while 1 {
expect {
"Is the new volume mounted and ready to go" {
take_from_tape $tapedevice $curr_tape
incr curr_tape 1
sleep 30
put_in..."
("foreach" body line 4)
invoked from within
"foreach filesystem { /dev/sda1 /dev/sda5 /dev/sdd5 /dev/md1} {
spawn /sbin/dump $dump_lvl$rest_of_dump $backuser@$hostdevice:$tapedevice
$blocksize 45..."
(file "/etc/backup.expect-russel-lvl" line 37)
k2 fails!
DUMP: short read error from /dev/md1: [sector -513674389]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674388]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674387]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674386]: count=512,
got=0
DUMP: bread: lseek2 fails!
DUMP: short read error from /dev/md1: [sector -513674385]: count=512,
got=0
DUMP: master/slave protocol botched.
DUMP: The ENTIRE dump is aborted.
Doug Freyubrger
>
> trying to dump from red hat 6.2 to a tape that is on a solaris 2.6 box
> the disk is mirrord, and tar to /dev/null works fine.
I trimmed like a hundred groups from the distribution list.
I trimmed out most of the lines to highlite the interesting ones:
> DUMP: Dumping /dev/md1 (/var/spool/imap) to /dev/rmt/0cn on host
> guesttp@police
A very active filesystem, contray to the instructions to have a filesystem
either offline or idle per the dump man page.
> DUMP: mapping (Pass I) [regular files]
> DUMP: mapping (Pass II) [directories]
> DUMP: dumping (Pass III) [directories]
> DUMP: dumping (Pass IV) [regular files]
Few people ever look at the above lines and think about what they imply. Dump
works on a raw device, not through the filesystem. If the filesystem changes
while it is running, it has no way of knowing that.
> DUMP: mapping (Pass I) [regular files]
First (Pass 1) every inode is scanned to see if it is newer mtime/ctime than
the reference time. All inodes to be backed up are put into a list, and the
information stored includes there sizes (critical data later on in the tale).
> DUMP: mapping (Pass II) [directories]
Next (Pass 2) the root directory of the device is put in the list and a
dependency tree is built to ensure that all inodes being backed up have
directory entries. If needed, parent directory inodes are found and added to
the list. Once again, the sizes of all inodes invloved are stored at that time
(critical data later if a directory shrinks somehow, this is way a directory
retains its blocks when child files are deleted, BTW). In the process all of
the inodes that are directories are sorted into dependency order.
> DUMP: dumping (Pass III) [directories]
Next (Pass 3) the inodes in the list that are directories are dumped to tape.
If a directory were to shrink between Phase 2 and Phase 3, you would get an
error here.
Most of the time the above 3 passes are fairly fast, and most of the time the
filesystem does not change enough to have much impact even if it is mounted.
> DUMP: dumping (Pass IV) [regular files]
This phase can take a long time in many cases. Each non-directory to be
backed up is copied to tape in inode order. Note that the exact length
to be backed up was recorded in an earlier phase. If a file is unchanged
during that time-span that entire file is backed up. If a file grows, only the
blocks that existed at the start are backed up. If a file is deleted (vi and
IMAP tend to recycle the inode, but emacs and POP tend to create new files and
delete the old ones) then you get a complaint that an inode has vanished.
If a file is truncated during the time span sice the earlier passes, like an
IMAP client reading and deleting a message, dump knew how many bytes to dump,
but the file now longer has that many bytes. Dump tried to read off the end
of the file, past its end. The result is an error like this:
> DUMP: bread: lseek fails
> DUMP: short read error from /dev/md1: [block -1686942968]: count=4096,
> got=0
> DUMP: bread: lseek2 fails!
Yup, you backed up an active filesystem. It takes a very high level of activity
to catch dump between phases.
For what it's worth, if you switch from "mailbox format" to "maildir format"
for your e-mail, there will be far more files but each one will be smaller.
You will encounter these errors far less often. Maildir format has its own
price if your users keep a lot of messages, though. It's a tradeoff.