On Oct 15, 2011, at 6:14 AM, Edward Ned Harvey wrote: >> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- >> boun...@opensolaris.org] On Behalf Of Tim Cook >> >> In my example - probably not a completely clustered FS. >> A clustered ZFS pool with datasets individually owned by >> specific nodes at any given time would suffice for such >> VM farms. This would give users the benefits of ZFS >> (resilience, snapshots and clones, shared free space) >> merged with the speed of direct disk access instead of >> lagging through a storage server accessing these disks. > > I think I see a couple of points of disconnect. > > #1 - You seem to be assuming storage is slower when it's on a remote storage > server as opposed to a local disk. While this is typically true over > ethernet, it's not necessarily true over infiniband or fibre channel.
Ethernet has *always* been faster than a HDD. Even back when we had 3/180s 10Mbps Ethernet it was faster than the 30ms average access time for the disks of the day. I tested a simple server the other day and round-trip for 4KB of data on a busy 1GbE switch was 0.2ms. Can you show a HDD as fast? Indeed many SSDs have trouble reaching that rate under load. Many people today are deploying 10GbE and it is relatively easy to get wire speed for bandwidth and < 0.1 ms average access for storage. Today, HDDs aren't fast, and are not getting faster. -- richard -- ZFS and performance consulting http://www.RichardElling.com VMworld Copenhagen, October 17-20 OpenStorage Summit, San Jose, CA, October 24-27 LISA '11, Boston, MA, December 4-9 _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
