Hi, Does anyone heard about having any plans to support thin devices by ZFS? I'm talking about the thin device feature by SAN frames (EMC, HDS) which provides more efficient space utilization. The concept is similar to ZFS with the pool and datasets, though the pool in this case is in the SAN frame itself, so the pool can be shared among different systems attached to the same SAN frame.
This topic is really complex but I'm sure it's inevitable to support for enterprise customers with SAN storage, basically it brings the differentiation of space used vs space allocated, which can be a huge difference in a large environment, and this difference is major even on the financial level as well. Veritas already added support to thin devices, first of all support to VxFS to be "thin-aware" (for example how to handle over-subscribed thin devices), then Veritas added a feature called SmartMove, a nice feature to migrate from fat to thin devices, and the most brilliant feature of all (my personal opinion, of course) is they released the Veritas Thin Device Reclamation API, which provides an interface to the SAN frame to report unused space at the block level. This API is a major hit, and even though SAN vendors today doesn't support it, HP and HDS already working on it, and I assume EMC has to follow as well. With this API Veritas can keep track of files deleted for example, and with a simple command once a day (depending on your policy) it can report the unused space back to the frame, so thin devices [b]remain[/b] thin. I really believe that ZFS should have support to thin devices, especially referring to the feature what this API brings into this field, as it can result a huge cost difference to enterprise customers. Regards, sendai -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
