Joerg Schilling wrote: > Carson Gaspar<[EMAIL PROTECTED]> wrote: > >> Louwtjie Burger wrote: >>> Dumping a large file from memory using tar to LTO yields 44 MB/s ... I >>> suspect the CPU cannot push more since it's a single thread doing all the >>> work. >>> >>> Dumping oracle db files from filesystem yields ~ 25 MB/s. The interesting >>> bit (apart from it being a rather slow speed) is the fact that the speed >>> fluctuates from the disk area.. but stays constant to the tape. I see up to >>> 50-60 MB/s spikes over 5 seconds, while the tape continues to push it's >>> steady 25 MB/s. > ... >> Does your tape drive compress (most do)? If so, you may be seeing >> compressible vs. uncompressible data effects. > > HW Compression in the tape drive usually increases the speed of the drive.
Yes. Which is exactly what I was saying. The tar data might be more compressible than the DB, thus be faster. Shall I draw you a picture, or are you too busy shilling for star at every available opportunity? -- Carson _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
