J: pretty sure it has no/minimal impact since it is performing the equivalent of a snapshot operation of just dropping a pointer to blocks of data. It also has to mark blocks of disk as 'clean' now that they're free. Minimal impact. Also consider that asis requires nearstore option which will additional 256k of ram for additional snapmirror stream that it allows. Again, vry minimal impact.
As to snapmirror footprint...it will send 700m over, but if dest. Isn't SIS'd, it will return to 1gb
I could be wrong in both points above so open to be corrected.
Good weekend to all. **Sent using wireless handheld... please excuse any typo's or brevity** Kevin Parker - NWN Corporation www.nwnit.com
-----Original Message----- From: "Page, Jeremy" jeremy.page@gilbarco.com To: "toasters@mathworks.com" toasters@mathworks.com Sent: 10/26/2007 3:10 PM Subject: A-SIS questions
I have read some of the info on how A-SIS works but I have a couple of questions: 1) Assuming an average compression rate (say /home with random docs in it) how much of a performance hit does it impose 2) Does it change how much data is sent over the wire when you use SnapMirror/SnapVault? I.e. if I get 30% compression on a 1 gig snapshot do I send 1 gig or 700 mb to update my target?
Oh, and for the folks who helped earlier, we are moving our Oracle and ESX systems to NetApp, the pSeries will be fibre connected, at least at first but the ESX stuff is all going on NFS.
~Jeremy
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There is CPU impact from calculating the MD5 sums on each block as well as storage overhead for keeping track of all the blocks in the system, to compare them for deduplicating.
The magnitude of the impact will probably be proportional to both the number of unique files/blocks in the system and the frequency of updates.
There is no such thing as a free lunch, sorry.
From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Kevin Parker Sent: Saturday, 27 October 2007 5:24 AM To: Page, Jeremy; toasters@mathworks.com Subject: RE: A-SIS questions
J: pretty sure it has no/minimal impact since it is performing the equivalent of a snapshot operation of just dropping a pointer to blocks of data. It also has to mark blocks of disk as 'clean' now that they're free. Minimal impact. Also consider that asis requires nearstore option which will additional 256k of ram for additional snapmirror stream that it allows. Again, vry minimal impact.
As to snapmirror footprint...it will send 700m over, but if dest. Isn't SIS'd, it will return to 1gb
I could be wrong in both points above so open to be corrected.
Good weekend to all. **Sent using wireless handheld... please excuse any typo's or brevity** Kevin Parker - NWN Corporation www.nwnit.com
-----Original Message----- From: "Page, Jeremy" jeremy.page@gilbarco.com To: "toasters@mathworks.com" toasters@mathworks.com Sent: 10/26/2007 3:10 PM Subject: A-SIS questions
I have read some of the info on how A-SIS works but I have a couple of questions:
1) Assuming an average compression rate (say /home with random docs in it) how much of a performance hit does it impose
2) Does it change how much data is sent over the wire when you use SnapMirror/SnapVault? I.e. if I get 30% compression on a 1 gig snapshot do I send 1 gig or 700 mb to update my target?
Oh, and for the folks who helped earlier, we are moving our Oracle and ESX systems to NetApp, the pSeries will be fibre connected, at least at first but the ESX stuff is all going on NFS.
~Jeremy
This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.
_____
Note: This message and any attachments is intended solely for the use of the individual or entity to which it is addressed and may contain information that is non-public, proprietary, legally privileged, confidential, and/or exempt from disclosure. If you are not the intended recipient, you are hereby notified that any use, dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the original sender immediately by telephone or return email and destroy or delete this message along with any attachments immediately.
Paul,
Is this statement your theory or do you have actual experience with running A-SIS?
There is CPU impact from calculating the MD5 sums on each block as well as storage overhead for keeping track of all the blocks in the system, to compare them for deduplicating.
The magnitude of the impact will probably be proportional to both the number of unique files/blocks in the system and the frequency of updates.
There is no such thing as a free lunch, sorry.
*From:* owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] *On Behalf Of *Kevin Parker *Sent:* Saturday, 27 October 2007 5:24 AM *To:* Page, Jeremy; toasters@mathworks.com *Subject:* RE: A-SIS questions
J: pretty sure it has no/minimal impact since it is performing the equivalent of a snapshot operation of just dropping a pointer to blocks of data. It also has to mark blocks of disk as 'clean' now that they're free. Minimal impact. Also consider that asis requires nearstore option which will additional 256k of ram for additional snapmirror stream that it allows. Again, vry minimal impact.
As to snapmirror footprint...it will send 700m over, but if dest. Isn't SIS'd, it will return to 1gb
I could be wrong in both points above so open to be corrected.
Good weekend to all. **Sent using wireless handheld... please excuse any typo's or brevity** Kevin Parker - NWN Corporation www.nwnit.com
-----Original Message----- From: "Page, Jeremy" jeremy.page@gilbarco.com To: "toasters@mathworks.com" toasters@mathworks.com Sent: 10/26/2007 3:10 PM Subject: A-SIS questions
I have read some of the info on how A-SIS works but I have a couple of questions:
- Assuming an average compression rate (say /home with random docs
in it) how much of a performance hit does it impose
- Does it change how much data is sent over the wire when you use
SnapMirror/SnapVault? I.e. if I get 30% compression on a 1 gig snapshot do I send 1 gig or 700 mb to update my target?
Oh, and for the folks who helped earlier, we are moving our Oracle and ESX systems to NetApp, the pSeries will be fibre connected, at least at first but the ESX stuff is all going on NFS.
~Jeremy
This message (including any attachments) contains confidential and/or proprietary information intended only for the addressee. Any unauthorized disclosure, copying, distribution or reliance on the contents of this information is strictly prohibited and may constitute a violation of law. If you are not the intended recipient, please notify the sender immediately by responding to this e-mail, and delete the message from your system. If you have any questions about this e-mail please notify the sender immediately.
Note: This message and any attachments is intended solely for the use of the individual or entity to which it is addressed and may contain information that is non-public, proprietary, legally privileged, confidential, and/or exempt from disclosure. If you are not the intended recipient, you are hereby notified that any use, dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please notify the original sender immediately by telephone or return email and destroy or delete this message along with any attachments immediately.
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Kevin Parker -
M. Vaughn Stewart -
Paul Rosham