Hi, I have recently (six weeks ago) switched all the filesystems on my PC from 'ext3' to JFS for various reasons, in part because I like the JFS design, in part because I had discovered that over the past several months my 'ext3' ''root'' filesystem performance had degraded by 7 times over that of a freshly loaded copy of itself.
So I have decided to compare the read speed of my ''root'' JFS filesystem as it is now, after six weeks of in-place package upgrades, and how it would be if I reloaded it. I have an otherwise quiescent disc, and I copied my ''root'' filesystem to it first as a partition image, to preserve the ''used'' layout, and then by 'tar', so that it would be reloaded in an optimal ''new'' layout. The filesystem contains around 7.5GiB of data in 360k files, and 2.3GiB are free. The result is that a whole-filesystem 'tar c' on the ''new'' layout takes 10min., on the ''used'' layout takes 26min., which is a factor of over 2.5 times longer. I have also done some spot checks on some largish files that I know have been regularly updated/rewritten, and there are similar slowdowns (no slowdown on files that have not been updated in the past six weeks). Details here: http://WWW.sabi.co.UK/Notes/anno05-4th.html#051101 Now 2.5 times is a lot better than 7 times (but the latter was over a rather longer period on a filesystem with less free space), but it is still somewhat disappointing, as the average transfer rate for reading the whole filesystem goes down (on a disc capable of around 35MiB/s sustained in optimal single-large-file conditions) from 12MiB/s, which is reasonable, to 5MiB/s, which is not awesome. ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ Jfs-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jfs-discussion
