On Thu, Jul 3, 2014 at 4:50 PM, Ljubomir Ljubojevic centos@plnet.rs wrote:
Whatever we do, we need the ability to create a point-in-time history. We commonly use our archival dumps for audit, testing, and debugging purposes. I don't think PG + WAL provides this type of capability. So at the moment we're down to:
A) run PG on a ZFS partition and snapshot ZFS. B) Keep making dumps (as now) and use lots of disk space. C) Cook something new and magical using diff, rdiff-backup, or related tools.
Check out 7z from p7zip package. I use command:
7za a -t7z $YearNum-$MonthNum.7z -i@include.lst -mx$CompressionMetod -mmt$ThreadNumber -mtc=on
Seems to be that 7zip uses LZMA for the 7z archives (though it supports other compression types). Confirmed below.
for compressing a lot of similar files from sysinfo and kernel.log, files backuped every hour that do not change much. And I find out that it reuses already existing blocks/hashes/whatever and I guess just reference them with a pointer instead of storing them again.
So, 742 files that uncompressed have 179 MB, compressed ocupy only 452 KB, which is only 0.2% of original size, 442 TIMES smaller :
Listing archive: 2014-03.7z
-- Path = 2014-03.7z Type = 7z Method = LZMA
Exactly ... LZMA ... Grab the "xz" package for CentOS 6
There's also an --lzma option for tar.
I am inclined to use xz utils as opposed to 7zip since 7zip comes from a 3rd party repo.