gaddesai
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What is the relation or difference between mirror,clone and copy?

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wallacealaswad
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Re: What is the relation or difference between mirror,clone and copy?

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TimeFinder/Mirror: Symmetrix TimeFinder/Mirror is essentially a business continuance solution that allows the use of special business continuance volume (BCV) Symmetrix devices. Copies of data from a standard Symmetrix device (which are online for regular I/O operations from the host) are sent and stored on BCV devices to mirror the primary data. Uses for the BCV copies can include backup, restore, decision support, and applications testing. Each BCV device has its own host address, and is configured as a stand-alone Symmetrix device.

TimeFinder/Clone: Creates full-device and extent-level point-in-time copies.

  1. 1. You can create up to 16 active clones of a single source volume, all of which are immediately available for both read and write access.
  2. 2. A differential clone session uses two (2) copy sessions, therefore, you can only have a maximum of eight (8) differential clone sessions.
  3. 3. Also includes a “NOCOPY” option, which enables you to perform a copy process only when the actual data is requested.
  4. 4. TimeFinder/Clone is ideal when high performance, RAID 5 and RAID 6 protection, and highly functional point-in-time copies are required.
  5. 5. TimeFinder/Clone supports Thick to Thin replication
  6. 6. The source and target of the replication operation can also be different RAID protection levels. An unprotected device can be replicated to a RAID protected device, but you cannot replicate a protected volume to an unprotected volume.
  7. 7. TimeFinder/Clone support for Thick to Thin replication is supported on EFD, Fibre Channel drives, and SATA drives

TimeFinder Clone and TimeFinder Mirror uses two different operations and rules

TimeFinder Clone: symclone

When you create the session between the Source and target, the Source will be in RW state and Target in Not Ready state. (SR:RW& Tgt:NR)

Once you activate the session, both the source and the target will be in RW state. (SR:RW& Tgt:RW)

TimeFinder Mirror: symmir

Associate session: At this state there is no copying yet. and both standard and BCV devices are RW. (SR:RW& Tgt:RW)

Establish session: Create the relationship between the std and bcv device, at this stage the standard devices is RW and BCV is not ready (SR:RW & tgt:NR)

Once you split the relationship, both standard and BCV are in RW state (SR:RW& Tgt:RW)

From the above, the symclonde activate is equivalent to symmir split command where both Source and Target can be modified, enabled and disabled.

Please see page 118 -table 3 for details mapping of the TimeFinder/Mirror operation to their TimeFinder/Clone operational equivalents.

https://support.emc.com/docu59409_Solutions-Enabler-TimeFinder-Family-8.0.3-CLI-User-Guide.pdf?langu...

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Jasonc1
3 Argentium

Re: What is the relation or difference between mirror,clone and copy?

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It's quite a broad question you've posted. To get a high level overview of Timefinder operations, take a look at the "EMC Solutions Enabler Symmetrix TimeFinder Family CLI Product Guide"

It describes each of the different TimeFinder modes. If you have any specific questions from your reading, I'd be happy to respond.

wallacealaswad
1 Nickel

Re: What is the relation or difference between mirror,clone and copy?

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TimeFinder/Mirror: Symmetrix TimeFinder/Mirror is essentially a business continuance solution that allows the use of special business continuance volume (BCV) Symmetrix devices. Copies of data from a standard Symmetrix device (which are online for regular I/O operations from the host) are sent and stored on BCV devices to mirror the primary data. Uses for the BCV copies can include backup, restore, decision support, and applications testing. Each BCV device has its own host address, and is configured as a stand-alone Symmetrix device.

TimeFinder/Clone: Creates full-device and extent-level point-in-time copies.

  1. 1. You can create up to 16 active clones of a single source volume, all of which are immediately available for both read and write access.
  2. 2. A differential clone session uses two (2) copy sessions, therefore, you can only have a maximum of eight (8) differential clone sessions.
  3. 3. Also includes a “NOCOPY” option, which enables you to perform a copy process only when the actual data is requested.
  4. 4. TimeFinder/Clone is ideal when high performance, RAID 5 and RAID 6 protection, and highly functional point-in-time copies are required.
  5. 5. TimeFinder/Clone supports Thick to Thin replication
  6. 6. The source and target of the replication operation can also be different RAID protection levels. An unprotected device can be replicated to a RAID protected device, but you cannot replicate a protected volume to an unprotected volume.
  7. 7. TimeFinder/Clone support for Thick to Thin replication is supported on EFD, Fibre Channel drives, and SATA drives

TimeFinder Clone and TimeFinder Mirror uses two different operations and rules

TimeFinder Clone: symclone

When you create the session between the Source and target, the Source will be in RW state and Target in Not Ready state. (SR:RW& Tgt:NR)

Once you activate the session, both the source and the target will be in RW state. (SR:RW& Tgt:RW)

TimeFinder Mirror: symmir

Associate session: At this state there is no copying yet. and both standard and BCV devices are RW. (SR:RW& Tgt:RW)

Establish session: Create the relationship between the std and bcv device, at this stage the standard devices is RW and BCV is not ready (SR:RW & tgt:NR)

Once you split the relationship, both standard and BCV are in RW state (SR:RW& Tgt:RW)

From the above, the symclonde activate is equivalent to symmir split command where both Source and Target can be modified, enabled and disabled.

Please see page 118 -table 3 for details mapping of the TimeFinder/Mirror operation to their TimeFinder/Clone operational equivalents.

https://support.emc.com/docu59409_Solutions-Enabler-TimeFinder-Family-8.0.3-CLI-User-Guide.pdf?langu...

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