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dynamox
6 Thallium

Reproduce TimeFinder/Clone functionality on VMAX3

Hello guys/gals,

I am trying to reproduce TimeFinder/Clone functionality on VMAX3. I would prefer not to use "emulation" and achieve the same thing using symsnapvx. One requirement is that clone target is a fully copy and not just a snapshot.  Here are the steps that i am attempting:

1) create target TDEVs same size as source TDEVs, add them to a storage group.

2) create snapshot

symsnapvx -sid 123 -sg sg_oracle -name snap establish

3) link to target TDEV, specify -copy to get full copy

symsnapvx -sid 123 -sg sg_oracle -snapshot_name snap link -copy -lnsg sg_snaptarget

so far so good, i can SRP utilization go up so it's making a full copy.

4) next i need to perform symsnapvx equivalent of symclone recreate. I don't see any options but to establish snapshot again

symsnapvx -sid 123 -sg sg_oracle -name snap establish


5) next i relink to target devices


symsnapvx -sid 123 -sg sg_oracle -snapshot_name snap relink -copy -lnsg sg_snaptarget



So these steps appear to achieve what i typically do with symclone, except for one thing. When i look at snapshots i see two snapshots with the same name.  I don't want multiple snapshots, i just need the one that i just established.  I can't terminate gen 1 snapshots because that will break "incremental" nature of this approach ? Am i understanding correct ?  If that's the case what are my options, setting TTL on each snapshot and let it auto expire after 25 hours or so ?



symsnapvx -sid 123 -sg sg_oracle list   -detail

Storage Group (SG) Name   : sg_oracle

SG's Symmetrix ID         : 0000000123    (Microcode Version: 5977)

------------------------------------------------------------------------------------------------------------------------

                                                                          Total

Sym                                         Flgs                          Deltas     Non-Shared

Dev   Snapshot Name                    Gen  FLRG Snapshot Timestamp       (Tracks)   (Tracks)   Expiration Date

----- -------------------------------- ---- ---- ------------------------ ---------- ---------- ------------------------

000B3 snap                                0 .X.. Mon Feb 15 05:03:38 2016          0          0                       NA

      snap                                1 .... Mon Feb 15 04:43:22 2016          0          0                       NA

                                                                          ---------- ----------

                                                                                   0

Thoughts ?

Thank you

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21 Replies
PedalHarder
3 Argentium

Re: Reproduce TimeFinder/Clone functionality on VMAX3

I don't think the copy feature of SYMSNAPVX is there to support the legacy CLONE COPY feature. I would be interested to know if there is a technology reason to use COPY (outside cascade operations) with snapvx in your environment.

As I understand it, when using cascade SYMSNAPVX, you have a dependency on terminating the the cascading snaps in reverse order typically (can't terminate the original source>tgt if there are cascades). If the original source>tgt snapvx is set to copy (and all tracks copied), this relationship may be terminated, even if the TGT is a source for a cascaded snapvx.

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PedalHarder
3 Argentium

Re: Reproduce TimeFinder/Clone functionality on VMAX3

Edit: relink -copy should provide the function you are after. I see that there are 2 instances of snapshot name "snap" in your output. Let me look at this in more detail....

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dynamox
6 Thallium

Re: Reproduce TimeFinder/Clone functionality on VMAX3

Jasonc,

reason i am doing -copy is because target devices  needs to be an R1, according to timefinder docs it requires -copy.

As you can see in step 5 i am using relink -copy but how do i "refresh" my snapshot so that it's an incremental copy. I don't see a recreate command for the snapshotvx, i only see establish. When i run establish with the same name as my previous snapshot ..it creates a new one.

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echolaughmk
3 Zinc

Re: Reproduce TimeFinder/Clone functionality on VMAX3

The relink command is the recreate from my experience since it will incrementally re-sync from the source to the linked target. You would likely create a new snapshot form the prod volume for the updated PiT image and then issue a relink from that snapshot to your existing linked target and it will be an incremental refresh, so your #4/#5 above is the way that I am aware of.There is no recreate that I am aware of with snapvx.....I think your procedure above is correct and the intended process.

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dynamox
6 Thallium

Re: Reproduce TimeFinder/Clone functionality on VMAX3

Thank you Keith. How do you deal with "old" snapshots, do you set TTL when you create them or manually/script delete them ?

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echolaughmk
3 Zinc

Re: Reproduce TimeFinder/Clone functionality on VMAX3

I have done both, but tend to do with the manual deletion or script it as cleanup upon creation of a new one just because of preference/control versus anything else really.

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dynamox
6 Thallium

Re: Reproduce TimeFinder/Clone functionality on VMAX3

something is not right. Everytime i run this command:

symsnapvx -sid 123 -sg sg_oracle -snapshot_name snap relink -copy -lnsg sg_snaptarget


even if i did not create a new snapshot, output from "symsnapvx -sid 123   -sg sg_oracle list   -linked -detail -gb" shows that it's performing a full copy. Same snapshot, nothing changing, i am simply re-running the same relink command. Any thoughts ?

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echolaughmk
3 Zinc

Re: Reproduce TimeFinder/Clone functionality on VMAX3

hmm...you have the -copy which is what makes it incremental so I wouldn't expect a full push. Does the -summary listing show anything different?

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dynamox
6 Thallium

Re: Re: Reproduce TimeFinder/Clone functionality on VMAX3

same thing, shows how much is remaining to copy

symsnapvx -sid 123 -sg sg_oracle -snapshot_name snap list -summary -gb

Storage Group (SG) Name : sg_oracle

  Snapshot  State               Count

  -----------------------      ------

  Restored                          0

  RestoreInProg                     0

  Established                       2

  EstablishInProg                   0

  Linked                            0

  CopyInProg                        1

  Copied                            0

  NoSnapshot                        0

  Failed                            0

  -----------------------      ------

  Total                             3

                              GB(s)

                              -------

Total Remaining                 157.3

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