EqualLogic Replication

Question

Hi folks, I'm hoping that someone can give me some advice on EqualLogic replication. I have created a Volume - 1600GB in size and this has been set to replicate to a partner. The portion I am not understanding if the total replication reserve - I have set this to 160% of the volume - ie. the reserve should be 2560GB However, the actual 'total replica reserve' within group manager is stated as 256GB. I have noticed that the 'Current replica volume reserve' is stating that it is 160GB - this then tallies with the figure above. I assume this figure is data currently on the volume although I cannot confirm this. Does this mean that you should configure replication once the volume has been setup with all the virtual machines and data? If not, and I add 1000GB of data to the volume and it has already replicated numerous times, what happens to the total replica reserve sizes? Do they update automatically or do I need to setup replication again for the figures to be correct? Would this amount of data change after initial replication cause replication issues or failures? Thanks for all your help Rob

michaelpacheco · Accepted Answer

Hello, RobertPBham...

Total Replica Reserve is a percentage of the Current Replica Volume reserve that provides additional space for replicas. If Current Replica Volume reserve is 160 GB at the moment, and the Total Replica reserve % is set to 160%, then the Total Replica Reserve size is 256 GB (160 GB x 160%).

If the Current Replica Volume reserve then increases, then the Total Replica reserve size also automatically increases accordingly.

I hope that helps. Please let me know if I can provide additional information.

Have a great day!

RobertPBham · Answer

Hi Donald,

Thanks for the reply - I've probably missed a little info out which doesn't help. The main site has multiple volumes of varying sizes. The DR site has delegated space of approximately 8.5TB.

The information above is what I see when I go to configure replication for a volume:

Volume1 - 1600GB

Local Reserve - 15% - 240GB (allowing for 240GB worth of data changes while replication takes place)

When I set the total replication reserve to 160%, I would expect this to list the total as 2560GB - 1600GB (100%) for the volume and 960GB (60%) - this comes out of the delegated space. However, the total replication reserve is listed as 256GB - this is 10% of what the replication reserve should be. This is much much smaller than I expect and cannot fathom out why?

Does that explain my query any better?

My worry is that if I add 1000GB data to the volume after replication is configured, this will be far over the 256GB that has been reserved - when it should be 2560GB, and cause a failure.

Thanks

Rob

RobertPBham · Answer

Hi Michael,

That's really helpful - thank you!

So it doesn't matter how much you add to the volume after initial replication has taken place - it will just automatically resize the replication to the correct size settings based on the percentages you have specified - is that correct?

Thanks

Rob

michaelpacheco · Answer

Hello, RobertPham...

Ideally, the Total Replica Reserve % values should be sized based on your knowledge of data change rate of the replica. If the Total Replica Reserve % is set to a very low value, and the replica size suddenly exceeds that value, then manual intervention could be required to increase the reserve percentage so that an in-progress replica can continue. Also, the total amount of configured reserve space must still fit within the delegated space. If there is insufficient delegated space on the secondary group, the system will require manual administrative intervention to increase the amount of delegated space.

Have a wonderful day!

EqualLogic

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