SHUTTER@ithaca.bitnet (04/06/88)
Hello, Well I've installed Ultrix v2.2 -- and it went rather smoothly, that is until I tried to perform backup. I have a csh script that runs the dump command, and it died a horrible death when I tried to run it. During weekly and monthly backups, we shut the system down to single user mode, sync, then perform a umount -a <--- this is the killer. Without any warning in the release notes and with the idea to save space on the root partition, DEC has moved /bin/csh to /usr/bin/csh and soft linked the two. They also did this with awk and mt. Unfortunately I needed all of those inorder for this script to work. I guess this letter is a warning to others who may have scripts they run when the /usr file system is unmounted and a feeler to see how many other people don't think this was quite right. As an aside -- how safe is it to backup filesystems while in single user mode without unmounting them? Thanks Wendy Shutter Academic Computing Ithaca College (bitnet: shutter@ithaca)
avolio@decuac.dec.com (Frederick M. Avolio) (04/14/88)
Wendy et al. (Wendy, didn'T I meet you at DECUS???) It is quite safe to dump a mounted file system. Actually, on decuac, we dump file systems while the system is multi-user. What, me scared??? Nahhhh. If you want to wimp out ( :-) ) and run dumps on a quiet system, just shut it down to single user, but leave everything mounted. I guess you might want to do an fsck, but would someone who runs dumps on a live system care about fsck??? Actually, the system assumes that everything is okay unless the system crashes and so should you... Fred [ I just do the equivalent of "umount -a ; mount -r /usr" before doing backups on our system. -- Art Z. ]
tjfs@otter.hple.hp.com (Tim Steele) (04/14/88)
...or who write their scripts using csh not sh! I *always* use sh to avoid these nastinesses, and because the 'sh' command language seems to work better when it comes to doing baroque things with loops. Tim
SHUTTER@ithaca.bitnet (04/21/88)
>...or who write their scripts using csh not sh! I *always* use sh to avoid >these nastinesses, and because the 'sh' command language seems to work better >when it comes to doing baroque things with loops. The mistake in my script wasn't whether it was csh or sh, it was the moving of some commands from /bin to /usr/bin. If DEC is going to offer both shells with it's operating system, then I should have a choice as to which I want to use. Sytem management is part paranoia, part common sense and part style. My 'style' is using both sh and csh equally when writing scripts. As a result, hopefully, I can assist user in questions about either. In case you forgot the orginal message, DEC also moved awk and mt to /usr/bin. Using those commands, in either shell, would have resulted in the same problem. Wendy Shutter
cudcv%DAISY.WARWICK.AC.UK@cunyvm.cuny.edu (Rob McMahon) (04/21/88)
In article <29937@felix.UUCP> avolio@decuac.dec.com (Frederick M. Avolio) writes >Wendy et al. (Wendy, didn'T I meet you at DECUS???) It is quite safe >to dump a mounted file system. Actually, on decuac, we dump file systems >while the system is multi-user. What, me scared??? Nahhhh. We do incremental dumps like this every day, and it has yet to get us into trouble, although I am conscious that one day the dump is going to be unusable when we need it and we'll have to go back to the previous one, so I am still slightly nervous about it. Just do it at a quiet time of day, and don't do level 0 dumps this way, it's too important if they go wrong. >If you want to wimp out ( :-) ) and run dumps on a quiet system, just shut it >down to single user, but leave everything mounted. If you've shut it down to single user, why not umount the filesystem, for safety. At the least you should do a 'sync' to make sure the disk matches memory. >I guess you might want to >do an fsck, but would someone who runs dumps on a live system care about >fsck??? Don't do it! Running fsck on a mounted filesystem is asking for disaster. There are little unconsistencies that can occur while the filesystem is active, the ones that fsck -p is willing to clean up if the machine crashes. If you let fsck patch these on the disk while the system is active, I shudder at the consequences. Rob -- UUCP: ...!mcvax!ukc!warwick!cudcv PHONE: +44 203 523037 JANET: cudcv@uk.ac.warwick.cu ARPA: cudcv@cu.warwick.ac.uk Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England