Pawel Jakub Dawidek wrote: > On Mon, Jan 12, 2009 at 10:27:11AM -0800, Eric.Taylor at sun.com wrote: > >>Author: Eric Taylor <Eric.Taylor at Sun.COM> >>Repository: /hg/onnv/onnv-gate >>Latest revision: a56dffa8fba92a621cf92fa5c4fa69fbda2228aa >>Total changesets: 1 >>Log message: >>6770534 zvols do not observe character device semantics >> >>Files: >> update: usr/src/uts/common/fs/zfs/zvol.c > > > Doesn't it take a huge hit on performance? If I understand it correctly, > every single write to ZVOL will first go to ZIL. Am I right?
Every write through the character device (i.e. /dev/zvol/rdsk) will. > I'd prefer this to be either a dataset property or, even better, ZVOL be > treated as write-caching device and support DKIOCFLUSHWRITECACHE ioctl > to flush the cache. I can also see both of those beeing useful together. > > What do you think? If you don't mind the data being cached, go through the block interface (/dev/zvol/dsk) instead. - Eric
