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1020
September 22nd, 2010 04:00
Can someone please expalain the mirror positions of a sym dev ?
What exactly is the role of the mirror positions in a sym dev ?
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This post is more than 5 years old
2 Posts
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1020
September 22nd, 2010 04:00
What exactly is the role of the mirror positions in a sym dev ?
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psetags
14 Posts
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September 22nd, 2010 21:00
Purpose of having mirror positions is to highlight your devices protection levels. Prior to V-MAX, most devices occupied 2 mirror positions initially unless they were standalone devices, leaving 2 mirror positions available for Local and Remote replication options as there is a maximum of 4 mirror positions. With the introduction of the V-MAX we see RVA (Raid Virtual Architecture) whereby only 1 mirror position is initially occupied by the device, regardless of whether it is Mirrored,RAID5,RAID6 , freeing up an additional mirror position for local and remote replication options, not that all local replication methods require a mirror position. Hope this explains.
tavs1
2 Posts
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September 23rd, 2010 04:00
Thanks psetags ! that explains a lot.. Can you pl elaborate on "not that all local replication methods require a mirror position" ?
SKT2
2 Intern
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1.3K Posts
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September 23rd, 2010 19:00
Consider local replication as you are making a copy(BCV) of the production data. There is a standard and target(BCV) relation created between each of the source and target device involed. This target device takes the next mirror postion(third) . If you make another BCV which may be the last one you can.
Quincy561
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September 23rd, 2010 19:00
Except that in many cases (all cases for VMAX), a BCV does not take a mirror position because it is really a clone and not a true BCV mirror.
Booyah2
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185 Posts
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September 28th, 2010 06:00
Yep, whenever possible, a clone should be used these days.
I would venture to say that the additional mirror positions (these days) are occupied by either a RDF device or a Hot Spare and we are seeing less of the Hot Spare as well as it has become a dynamic device with permanent sparing. We may see more and more mirror positions being used by virtual LUN migrations, a nice new feature.