Your description of how the IP4700's Snapshot copy-on-write mechanism works is right on. The original data is copied to a new location and the new
data
is written to the original block. Yes this compromises performance. Yes you have to allocate physical disk space to accomplish this. No you cannot shrink the amount of disk space you have allocated for this process if you find that it is too much.
Hmm, not according to a demo we had from EMC week before last. I grilled them pretty hard on that and they claimed that they updated the inode file only and did not copy blocks to another location.
Well, we have an eval unit coming in next week and I'll do some testing.
Regards
Martin Enterprise Storage/Enterprise Server Group mailto:martin.hughes@halliburton.com cellphone: +1 713 303 9214 office: +1 281 871 4124
Did they prove that or just claim it. I can claim my car goes 150 mph and gets 60 miles per gallon. That doesn't make it true and doesn't make me credible just because I claimed it and refute when someone else says that it doesn't.
-----Original Message----- From: owner-dl-toasters@netapp.com [mailto:owner-dl-toasters@netapp.com]On Behalf Of Martin Hughes Sent: Thursday, May 10, 2001 9:45 AM To: toasters@mathworks.com Subject: RE: EMC IP4700 vs NetApp F740
Your description of how the IP4700's Snapshot copy-on-write
mechanism works
is right on. The original data is copied to a new location and the new
data
is written to the original block. Yes this compromises performance. Yes you have to allocate physical disk space to accomplish this. No
you cannot
shrink the amount of disk space you have allocated for this
process if you
find that it is too much.
Hmm, not according to a demo we had from EMC week before last. I grilled them pretty hard on that and they claimed that they updated the inode file only and did not copy blocks to another location.
Well, we have an eval unit coming in next week and I'll do some testing.
Regards
Martin Enterprise Storage/Enterprise Server Group mailto:martin.hughes@halliburton.com cellphone: +1 713 303 9214 office: +1 281 871 4124
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Ferd Berfl -
Martin Hughes