On Fri, Jun 27, 2003 at 09:20:45AM +0200, [EMAIL PROTECTED] wrote: > > I have an installation of MySQL where the data directory is located > on an NFS share. Client and server are connected by Full Duplex > Gigabit Ethernet (both hosts run Linux 2.4.21). The NFS is exported > with "sync" option. > > Read performance is really fine, but when it comes to > writing.... e.g. an ALTER TABLE writes the temporary table it > creates with a speed of ~25KB/sec. > > - Is the poor write performance in sync mode related to how MySQL > does its write accesses (I guess, because for a plain file copy I > get write rates of ~10MB/sec, which is 400 times faster than MySQL > writes)?
Wow. Perhaps MySQL is writing in significantly smaller blocks than when you copy a file. > - Is there any possibility of speeding up things? Apparently so... > - What would be the risks of exporting the NFS share with the > "async" option (the MySQL write rate improves nearly by factor > 1000 to ~20MB/sec then)? The risk is lost data if the NFS server dies. The MySQL server may think that data was committed to disk that was not. Jeremy -- Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo! <[EMAIL PROTECTED]> | http://jeremy.zawodny.com/ MySQL 4.0.13: up 24 days, processed 772,847,148 queries (365/sec. avg) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
