[opensuse] reiserfs journal on a separate device.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, I want to experiment placing the journal for a reiserfs on a separate device (the disk is on slow USB). What I see in "man mkreiserfs" is this: -j | --journal-device FILE FILE is the name of the block device on which is to be places the filesystem journal. -o | --journal-offset N N is the offset where the journal starts when it is to be on a separate device. Default is 0. N has no effect when the journal is to be on the host device. - From this I understand it has to be a dedicated partition, not a file in a filesystem. Is this so? Why? We can place the swap on a file. Why not a journal? I could use a loop filesystem, I guess, but it means jumping trough another "loop". -s | --journal-size N N is the size of the journal in blocks. When the journal is to be on a separate device, its size defaults to the number of blocks that the device has. When journal is to be on the host device, its size defaults to 8193 and the maximal possible size is 32749 (for blocksize 4k). The minimum size is 513 blocks (whether the journal is on the host or on a separate device). Now, what is the size? It says "the number of blocks that the device has". Which device, the one holding the reiserfs, or the one holding the journal? Also, the phrase "size is 32749", Is that blocks, or bytes? I assume blocks, but not sure because it says "size is 32749 (for blocksize 4k)". I hate when programmers write a documentation... it is very clear for those in the know, but for the rest of us common mortals it is like a trade secret. The documentation for the ext3 counterpart is a bit clearer: size=journal-size Create an internal journal (i.e., stored inside the filesystem) of size journal-size megabytes. The size of the journal must be at least 1024 filesystem blocks (i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.) and may be no more than 102,400 filesystem blocks. At least I know the minimum and maximum size, but not the optimal size. And the practicalities are worse: device=external-journal Attach the filesystem to the journal block device located on external-journal. The external journal must already have been cre- ated using the command mke2fs -O journal_dev external-journal Note that external-journal must have been created with the same block size as the new filesystem. In addition, while there is sup- port for attaching multiple filesystems to a single external journal, the Linux kernel and e2fsck(8) do not currently support shared external journals yet. Uau. Not only I have to dedicate to it a partition, but it has to have the same blocksize, and I can't share it for several devices (reiserfs can). Good grief! :-( - -- Cheers, Carlos Robinson -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) Comment: Made with pgp4pine 1.76 iD8DBQFGRwi/tTMYHG2NR9URAnPeAJ9XJlgtQOgRlSVb0eVuEfigBw5upwCeMy6e 1SPvAOqkwHUs2cFXW7eH5lc= =/VWY -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
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Carlos E. R.