cool.
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| Author | Content |
|---|---|
| techiem2 Mar 15, 2009 6:52 PM EDT |
I hadn't heard of this before. So if I understand it right, you have a box with a disk/partition/whatever, and you export it kind of like NFS and that export is connected to by another machine? Does this mean you could say, setup your fileserver with a nice big raid setup, then export partitions to your web server, print server, etc. to be used as storage on them with lower overhead than say NFS exports? |
| gus3 Mar 15, 2009 9:04 PM EDT |
Not quite. It isn't a server/client setup; the terms are "initiator" and "target" instead (note the singular). Just like it's a bad idea to have multiple VM's mounting the same physical partition on a real disk, it's also a bad idea to have multiple initiators controlling one target. Multiple writers can stomp on one filesystem, with disastrous results. AoE is basically a re-map of the AT Attachment command set into Ethernet. Because it doesn't involve the Internet protocol, it isn't "route-able" into other networks. And, the largest ATA packet can easily fit into an Ethernet packet, so the translation doesn't require expensive state-tracking the way IP (and TCP above it) do. It's suited for high-availability cluster setups, where one machine at a time controls the target and others wait for fail-over. That one machine may serve NFS or CIFS or something else, giving a many-to-one client/server setup, but that should be on a different layer than AoE. N.B.: This is what I have managed to glean; others may feel free to correct me. |
| DrDubious Mar 16, 2009 11:15 AM EDT |
It's more a replacement for iSCSI than NFS, really (hypothetically, AOE ought to have less overhead than iSCSI and therefore potentially better throughput.) |
| gus3 Mar 16, 2009 11:56 AM EDT |
On the network layer, AoE does have less overhead. iSCSI is wrapped in TCP/IP, which by definition involves a longer code path between the disk protocol and the wire. But that also makes iSCSI capable of reaching farther, conceivably to anywhere on the Internet, where AoE is restricted to the local Ethernet. |
| gus3 Mar 16, 2009 12:07 PM EDT |
I need to correct my first comment above. Some filesystems are specifically designed for multiple access, like OCFS and GFS. This would also make AoE an option for high-performance clusters, with multiple simultaneous access to the SAN. |
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