Re: *terrible* direct-write performance with raid5

2005-02-23 Thread Michael Tokarev
dean gaudet wrote: On Tue, 22 Feb 2005, Michael Tokarev wrote: When debugging some other problem, I noticied that direct-io (O_DIRECT) write speed on a software raid5 is terrible slow. Here's a small table just to show the idea (not numbers by itself as they vary from system to system but how

Re: *terrible* direct-write performance with raid5

2005-02-23 Thread Peter T. Breuer
Michael Tokarev [EMAIL PROTECTED] wrote: (note raid5 performs faster than a single drive, it's expectable as it is possible to write to several drives in parallel). Each raid5 write must include at least ONE write to a target. I think you're saying that the writes go to different targets from

Re: *terrible* direct-write performance with raid5

2005-02-22 Thread Peter T. Breuer
Michael Tokarev [EMAIL PROTECTED] wrote: When debugging some other problem, I noticied that direct-io (O_DIRECT) write speed on a software raid5 And normal write speed (over 10 times the size of ram)? is terrible slow. Here's a small table just to show the idea (not numbers by itself as

Re: *terrible* direct-write performance with raid5

2005-02-22 Thread Michael Tokarev
Peter T. Breuer wrote: Michael Tokarev [EMAIL PROTECTED] wrote: When debugging some other problem, I noticied that direct-io (O_DIRECT) write speed on a software raid5 And normal write speed (over 10 times the size of ram)? There's no such term as normal write speed in this context in my