What is Incremental SAN Copy in EMC Clariion ?

Incremental SAN Copy copies only changes to the destination(s). Changes are tracked by means of bitmaps, and, if required, a COFW process will be performed (both of which require that a Reserved LUN is assigned to the Session) Networks with speeds starting at T1 connections are supported. SAN Copy will perform a certain amount of optimization,depending on network speed. SAN Copy shares the ‘chunk’ size with SnapView - 64 KB so that a COFW copies 64 kB of data to the Reserved LUN. When the changed data must be copied to the secondary, only the 2 kB ‘sub-chunks’ that have changed are actually copied – this makes the link utilization much more efficient. The mark and unmark processes start and end the point in time copy process; the tracking of changes continues, though, and the ISC SnapView Session continues to run. SAN Copy is aware of which copies have succeeded, and can resume to failed destinations only. SAN Copy can recover from SP reboots and LUN trespasses.

Salient Features:-

1) Incremental copy

Changed data tracked at 64 KB granularity.

Data transferred at 2 kB granularity.

Map of tracked changes stored persistently.

2) Mark and Unmark operation

Affects state of ISC SnapView Session.

3) Modify Incremental Copy Session Properties

Turn on/off incremental tracking.

Link Bandwidth & Latency.

Sync Required (full copy).

4) Resume to only failed destinations

5) ISC-specific statistics

Time last marked.

Time copy started.

Blocks to copy in next incremental update.

6) Auto-Recovery (all SAN Copy Sessions)

SP Reboot.

LUN trespass.