On one server I use urbackup to also backup the postgresql database regularly, by activating it in “postgresbase.conf”.
It works. Mostly.
A lot of times I get a hash missmatch error. See below.
The Size of the Database is around 50GB, everyday a few 100MB are added, and the backup is executed daily. I get the error message about 2-3 times per week, even though there are some weeks where I don’t get any message at all.
A few months ago I’ve lost all urbackup data because of an BTRFS error, and had to do a full backup again. It took about 20 tries, until it managed to copy the whole database without showing the error message.
Postgresql is running inside of a virtual machine with several other virtual machins running parallel. It uses ECC-Memory. And everything works perfectly stable (the “to backup server” and the “urbackup server”). Both servers run Linux. When doing only the filebackups without the postgresbase backup, no error ever appeared.
I can’t find a single error in any system logfiles, also smartdata of the HDDs look perfect.
So I don’t really believe there is a problem with the memory or harddisk and I also don’t believe in that many accidental bit flips.
Urbackup server: 2.4.12
that here is the error message:
ERROR: Client calculated hash of “/var/lib/urbackup/example.com/200226-2004/urbackup_backup_scripts/postgresbase/base/20352/21044.15” differs from server calculated hash. This may be caused by a bug or by random bit flips on the client or server hard disk. Failing backup. (Hash: sha512-nosparse, client hash: AspA3C6lZXUnY3NtbzNXabsHn8lExcKE63D+ZfcjYbz6gvIZOuEE9Mk85Qd+MviCW+RICrHKGR0M1m/jNnGPbw==, server hash: q/o/i0SAIv9yFQXVk92m06BcvAFrOeHHKpHpb4GaPZjiRjZd/7p2V0P1ReFFbiFCXFFzgcUYQaLTS4VoXCGKiA==)
ERROR: Client calculated hash of “/var/lib/urbackup/example.com/200226-2004/urbackup_backup_scripts/postgresbase/base/20352/21044.33” differs from server calculated hash. This may be caused by a bug or by random bit flips on the client or server hard disk. Failing backup. (Hash: sha512-nosparse, client hash: hJvC9cue0qRXpv8bpqHeRHybUatrDgIZunHa6X4oWhvKcxyd1lEqDAGBhMwIaWYx1oeLBO4YTaTh1HKuaV/9HA==, server hash: vemRjhOj64Z0W8/gAF16liBAS8ItG143+6mUYfzAaFd7fmpgNp9ZdrG+HLgfKpaCshDVtd29XPyEBs3Bu4/WDw==)
ERROR: FATAL: Backup failed because of disk problems (see previous messages)
Is it possible there is a bug somewhere?