On Tue, Jul 15, 2008 at 12:50:57PM -0400, thomas62186218@xxxxxxx wrote: > Hi Ben, > > Nice reporting on the benchmarks. It would be helpful though to run > these tests without a file system involved, using a block level > benchmark utility like fio or similar to really measure the RAID > performance in isolation. While you did use a file system in both your > hardware and software RAID tests, before directly implicating software > RAID, it makes sense to isolate it as much as possible in the testing > by eliminating the file system for benchmarks. I think actually the use of the file systems is one of the strengths of this report. Many benchmarks are done only on the raw raid systems, and that gives some aritficial benchmarks that are only of theoretical interest, as the user really needs to have a FS to employ the raids. And the file system layer can compensate a lot for some characteristics of the raid types. I would actually welcome more tests with specific user profiles, like many small reads and writes for database use, and concurrent random reading and writing to simulate the load on a server. What bonnie++ is reporting is only equential IO. This is important on work stations, but actually not on servers. I have a new category - namely sequential reads on a system already running a workload of mostly random reading, but also some writing. this is important on some of my servers, like a ftp server. How fast can a new user get a file on an already loaded server? I dont know how to measure it in a reproducable way, but I do have some experimential figures. Best regards Keld -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
