> Given your question are you about to come back with a > case where you are not > seeing this?
Actually, the case where I saw the bad behavior was in Linux using the CFQ I/O scheduler. When reading the same file sequentially, adding processes drastically reduced total disk throughput (single disk machine). Using the Linux anticipatory scheduler worked just fine: no additional I/O costs for more processes. That got me worried about the project I'm working on, and I wanted to understand ZFS's caching behavior better to prove to myself that the problem wouldn't happen under ZFS. Clearly the block will be in cache on the second read, but what I'd like to know is if ZFS will ask the disk to do a long, efficient sequential read of the disk, or whether it will somehow not recognize that the read is sequential because the requests are coming from different processes? This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
