Re: Chunks Disappeared After Reboot!

>From: "Paul J. Reimold" <preimold@genacc-us.com> >Date: Wed, 04 Jun 1997 10:12:54 -0400 >X-Informix-List-Id: <news.38726> > >Here's the situation. NCR 5100M, Informix Online 7.12, EMC 5500 >Symmetrix array. NCR Disk Array Plus created virtual disks (vdisks) >striped across SCSI channels. > >Created links (chunk1,etc.) to vdisks in /dev/rdsk (raw chunks). Change >ownership of chunks and vdisk files to Informix. > >After power down/up, chunk link files are gone! vdisk files had original >root ownership and permissions. Some versions of Unix rebuild /dev each time they reboot, resetting the permissions, etc. These versions of Unix are a nuisance. >Luckily, I was able to recreate the chunk links and get the Informix >instance going, but it was quite a scare! > >Any ideas, thoughts out there? Incidently, I did not experience this >problem with chunks linked to partition slices rather than virtual >disks. Tip #1: do not use /dev/anything in the OnLine configuration files. I use a special directory like /ix.dev or /usr/informix/dev, and create the chunk devices there. $ ls -l /usr/informix/devtotal 18 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s23.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s29.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s31.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s37.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s41.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s43.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 root RAND 18 May 20 16:46 s47.rootdbs.c0 -> /dev/rdsk/c0t2d0s6 lrwxrwxrwx 1 informix informix 18 May 2 17:23 s53.rootdbs.c0 -> /dev/rdsk/c0t3d0s4 lrwxrwxrwx 1 informix informix 18 May 2 17:23 s53.sbspace.c0 -> /dev/rdsk/c0t3d0s4 $ Tip #2: Add a system-specific startup script which sets the Informix device permissions when the machine is started. This might go in /etc/init.d and /etc/rc2.d (on my Sun Solaris 2.5 machine, which is SVR4 look-alike, mostly). It would do something like: chown informix /usr/informix/dev/* chgrp informix /usr/informix/dev/* chmod 660 /usr/informix/dev/* Note that this will change the permissions on the actual device at the end of the chain of symbolic links, not on the symlinks themselves. If you want to get more fancy, you can also reset the permissions on the corresponding block device (for me, that's /dev/dsk/c0t2d0s6 and /dev/dsk/c0t3d0s4), so that the permissions are set to deny all access (chmod 0). That requires a slightly different (more complex) script. Yours, Jonathan Leffler (johnl@informix.com) #include <disclaimer.h>