On Fri, Oct 16, 2015 at 03:06:02AM +0000, Warner Losh wrote: > Author: imp > Date: Fri Oct 16 03:06:02 2015 > New Revision: 289405 > URL: https://svnweb.freebsd.org/changeset/base/289405 > > Log: > Do not relocate extents to make them contiguous if the underlying drive can > do > deletions. Ability to do deletions is a strong indication that this > optimization will not help performance. It will only generate extra write > traffic. These devices are typically flash based and have a limited number > of > write cycles. In addition, making the file contiguous in LBA space doesn't > improve the access times from flash devices because they have no seek time.
In reality, flash devices have seek time, about 0.1ms. Many flash devices can do 8 simultaneously "seek" (I think NVMe can do more). _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
