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Adding disks in bulk to an existing cluster
Afternoon all
We have an existing cluster, 14 nodes, each with 16 disks x 2TB. So quite a lot of storage then. However, we plan to add an additional 2 disks to each host, so that's 28 disks total I'll be adding to the cluster.
We're on R2_0.11000.174 at the moment, so before I go ahead, just wondered what the best way to do this would be? Should I look to add all 28 via script in as tight a window as possible and let ScaleIO sort it all out in one go - or should I perhaps add 2 to one node, let it rebalance to completion, add 2 to next, etc? It seems that staggering the operation is just going to create far more IO than is necessary, but I'd like some input from the experienced users/developers here if possible as to my best (and safest) way forward.
And are there any bugs I should perhaps be aware of in terms of adding such a large increase in storage/devices to an existing cluster? Just trying to protect against chaos so what's the safest way here?
Thanks for any advice
AW
andyinv
37 Posts
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September 1st, 2017 04:00
Anyone?
RHasleton1
73 Posts
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September 1st, 2017 09:00
HI Andy,
In a case like this, it would be best to just add the disks in one action (script), mainly to save you from having to do it multiple times. ScaleIO doesn't have any issues whether you want to add the disks a few at a time or all at the same time.
If you are worried about the IO impact to the clients, you can restrict the amount of IO each disk will handle for the rebalance in the GUI:
- Go to "By Storage Pools" in upper right hand corner
- Right-click on the storage pool and select "Set I/O Priority"
- Set the rebalance policy to throttle the limit (per device)
We have other customers that do the same thing, where the mass device add is scripted. That has worked just fine in all cases. One thing to be aware of is if they are all in the same storage pool, there is a maximum supported limit of 300 devices per storage pool and you will be at 252 after the new disks. It's just something to keep in mind for future planning.
Other than that, you're good to add them all at once!
Rick
andyinv
37 Posts
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September 5th, 2017 02:00
Perfect, thanks Rick !