Hi,for a tiny BackupPC instance with on an SSD+HDD-server, I want the HDD to be in standby mode (spinned down) most of the time. Hence, I only store __TOPDIR__ on it, and have everything else on the SSD. This almost works, except for the fact that unsuccessful pings write a log entry in __TOPDIR__/pc/$host/LOG.DDMMYYYY, and LOCK is touched. Which happens on every wakeup when some client is not reachable; in other words, too often.
AFAICS, from what's inside pc/, actually vital for the integrity of the backups are the nnn and refCnt dirs (and, to some extent, the backups and config.pl files). Those are only accessed during backup or restore jobs, when the "vault" disk is active anyway. So, in short, I want to bring __TOPDIR__/pc/$host/LOG* and LOCK from the HDD to somewhere else. Note that both LOG* and nnn are moving targets, so symlinks only work to a certain extent. (By the way: LOG.DDMMYYYY is actually LOG.MMYYYY, without DD, on my 4.1.3 installation.)
My usual approach is anything-sync-daemon (which uses an overlayfs to move some directory to tmpfs, and sync backs periodically and/or on user request). However, this only works at directory level, and would require moving the entire __TOPDIR__/pc directory to tmpfs. nnn can easily become large, and overlayfs is ill-suited for that. Another approach would be to move __TOPDIR__/pc to the SSD and rsync back each __TOPDIR__/pc/$host/ to the HDD in a DumpPostUserCmd and, perhaps, after each nightly. That's better, but again, the nnn can grow large (at least in number of files) and might become ill-suited even for the SSD and/or rootfs.
=> Question 1.) Short of patching BackupPC, does anyone have a suggestion or alternate solution I didn't think of?
It would be way easier to properly separate the two kinds of data if the location of the per-host LOG* and LOCK files would be configurable, e.g. to somewhere below __LOGDIR__. This would match the logic for the global LOCK (which resides at __LOGDIR__), even though I'd typically expect lock files to live below /run/lock or /var/run/lock. Full backward compatibility could be kept, e.g., through a __PERHOSTLOGDIR__ variable defaulting to __TOPDIR__/pc/.
I'd be willing to look into preparing a patch and pull request, if there is any interest. But I understand that the scenario and motivation are negligible in an enterprise setup, and that changing the storage layout can a royal pain in the * for existing systems. Hence,
=> Question 2.) Would such a change have any chance to be integrated in BackupPC? If so, under what constraints for the interface? Any recommendations for locations? What about {Xfer,Restore,Archive}{ERR,LOG,Info}*?
Best, Alex
smime.p7s
Description: S/MIME Cryptographic Signature
------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________ BackupPC-devel mailing list BackupPC-devel@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-devel Wiki: http://backuppc.wiki.sourceforge.net Project: http://backuppc.sourceforge.net/
