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207 Posts
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2838
September 30th, 2013 10:00
symmir vs symclone
Hello, we currently have DMX4s and will upgrade to VMAX next year. We have IBM mainframe, Unisys mainframe, AIX, Windows, VMware etc connected to the Symm arrays. We are using old style TimeFinder (symmir) with BCVs on our IBM mainframes.
Soon we will be implementing replication on our Unisys mainframe. It seems the new direction is towards symclone with standard volumes and away from good old symmir and BCVs. Is this correct? As we work on new projects for replication should we use symclone or symmir? Is there a stated direction from EMC? It seems like symclone has a definte advantage in that it does not need to use a mirror position.
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seancummins
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226 Posts
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October 14th, 2013 07:00
Brad,
The VMAX doesn't have true BCV mirrors anymore -- If you continue to use symmir with BCVs on VMAX, it will emulate BCVs (TF/Mirror), but will actually use clone technology in the background. I would definitely recommend that you switch to native symclone commands. With symclone, you'll be able to activate and use your clone targets before the background copy completes. If your host requests a block of data on the clone that hasn't been copied yet, the VMAX will transparently use CopyOnAccess to retrieve that block from the source volume, copy it to the clone target, and send it to the host that requested it.
Thanks,
- Sean
dynamox
9 Legend
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20.4K Posts
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October 14th, 2013 09:00
did you get a message about your post being moderated ?
brad12341
207 Posts
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October 14th, 2013 09:00
Sean, thanks for the input, good info.
It was strange I created this discussion a couple of weeks ago but never saw it get posted until today. Is there some process to getting these things posted in a timely manner?
AranH1
2.2K Posts
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October 15th, 2013 07:00
Agreed, I have also found that some operations have been blocked when using symmir and BCVs on a VMAX that would not be blocked if using symclone and standard devices. Best to update the scripts and go with symclone ...
LBM99
1 Rookie
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119 Posts
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October 15th, 2013 07:00
Symclone will be far more functional than symmir. Even though symmir uses clone in the background, it is TF Mirror Emulation and follows TF Mirror rules, behaving as if the BCV will occupy a mirror position on the source even though it is not really doing so. Symclone will allow you to do things that you will not be able to do with symmir, for example with cascading clones, or SRDF.
So yes, I would recommend moving to symclone commands.
Zhang_Jiawen
2 Intern
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1.2K Posts
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January 28th, 2014 04:00
Starting with Enginuity™ Version 5671, TimeFinder automatically maps a TimeFinder/Mirror command to the executable of the appropriate TimeFinder/Clone command when it encounters a BCV that is a RAID-5-or RAID-6 protected device. Under clone emulation mode, TimeFinder/Clone initiates the pre-copying of data.
When you establish a BCV pair under clone emulation, the symmir establish -full command maps to the symclone create -precopy -differential
command. This action causes copying to begin while still checking for new writes. The symmir split command maps to the symclone activate command. This action causes the data to become available to the host as an instant point-in-time copy.
For more information, I suggest you refer to EMC® Solutions Enabler Symmetrix® TimeFinder® Family CLI from support.emc.com.
brad12341
207 Posts
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January 28th, 2014 11:00
Great answer, thanks.