Re: wal-size limited to 16MB - Performance issue for subsequent backup

Hi.

One of our "production issues" is that the system generates lots of
wal-files, lots is like 151952 files over the last 24h, which is about
2.4TB worth of WAL files. I wouldn't say that isn't an issue by itself,
but the system does indeed work fine. We do subsequently gzip the files to
limit actual disk-usage, this makes the files roughly 30-50% in size.

That being said, along comes the backup, scheduled ones a day and tries to
read off these wal-files, which to the backup looks like "an awfull lot of
small files", our backup utillized a single thread to read of those files
and levels of at reading through 30-40MB/s from a 21 drive Raid50 of
rotating drives, which is quite bad. That causes a daily incremental run
to take in the order of 24h. Differential picking up larger deltas and
full are even worse.

Suggestions are welcome. An archive-command/restore command that could
combine/split wal-segments might be the easiest workaround, but how about
crash-safeness?