.TH "md_src_plugins_sync_README" 3elektra "Sun May 29 2016" "Version 0.8.14" "Elektra" \" -*- nroff -*-
.ad l
.nh
.SH NAME
md_src_plugins_sync_README \- README 

.IP "\(bu" 2
infos = Information about the sync plugin is in keys below
.IP "\(bu" 2
infos/author = Markus Raab markus@libelektra.org
.IP "\(bu" 2
infos/licence = BSD
.IP "\(bu" 2
infos/needs =
.IP "\(bu" 2
infos/provides =
.IP "\(bu" 2
infos/placements = precommit
.IP "\(bu" 2
infos/description = Makes sure that config file is written to disc
.PP
.PP
Storage plugins usually do not use fsync (2) for writing their file to disc\&. That means that the content of the file could be in some buffer and not on the hard disc\&.
.PP
This is good for power saving on laptops, but not a good idea on production use otherwise\&. So it is strongly recommended to always add this plugin\&.
.PP
.SS "Usage"
.PP
Just add this plugin to the list of plugins during mounting, e\&.g\&. 
.PP
.nf
    kdb mount file.dump /important dump sync

.fi
.PP
.PP
Then when you observe the change of a value, e\&.g\&. 
.PP
.nf
    strace kdb set user/important/key value

.fi
.PP
.PP
you can see, done by storage: 
.PP
.nf
    open("/home/markus/.kdb/file.dump.16874:1409592592.95084.tmp", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 4
    write(4, "kdbOpen 1\n", 10)             = 10
    write(4, "ksNew 1\n", 8)                = 8
    write(4, "keyNew 19 6\n", 12)           = 12
    write(4, "user/important/key\0value\0\n", 26) = 26
    write(4, "keyEnd\n", 7)                 = 7
    write(4, "ksEnd\n", 6)                  = 6
    close(4)                                = 0

.fi
.PP
.PP
then done by sync: 
.PP
.nf
    open("/home/markus/.kdb/file.dump.16874:1409592592.95084.tmp",
                    O_RDWR) = 4
    fsync(4)                                = 0
    close(4)                                = 0

.fi
.PP
.PP
and finally commit + sync of directory by resolver: 
.PP
.nf
    rename("/home/markus/.kdb/file.dump.16874:1409592592.95084.tmp",
                    "/home/markus/.kdb/file.dump") = 0
    stat("/home/markus/.kdb/file.dump", {st_mode=S_IFREG|0644,
                    st_size=69, ...}) = 0
    fcntl(3, F_SETLK, {type=F_UNLCK, whence=SEEK_SET, start=0,
                    len=0}) = 0
    close(3)                                = 0
    open("/home/markus/.kdb",
                    O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 3
    fsync(3)                                = 0
.fi
.PP