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How to disable "write cache mirroring" on EVA storage?

Cho,Hyun(Chris)
Occasional Visitor

How to disable "write cache mirroring" on EVA storage?

Hello, dear.

As title, Could anyone let me know how to disable "write cache mirroring" on EVA storage.
I think this feature does not same as write back or write through on write cache.
In order to increase almost heavy write performance up about 16%, it will be good.
In this configuration, Of course, I know if one controller fails, systems will be crashed.
Attached files are best practice performance on EVA. see page 13 for "write cache mirroring"

Thanks.
2 REPLIES
Uwe Zessin
Honored Contributor

Re: How to disable "write cache mirroring" on EVA storage?

In early version it was a selectable item in the GUI. These days it is still available in SSSU, however, when I try it with CV V6.0.2 against an EVA-4000:

E4K> set vdisk "\Virtual Disks\S2\S2-2\ACTIVE" mirrorcache=notmirrored

Error: Error cannot modify object properties. [Unsupported operation for AA mode]
E4K>

Looks like this feature is only available with active/passive EVAs. Maybe it has been removed to simplify the XCS firmware: if the I/O goes to the controller, which does not own the virtual disk, the data must be sent over a mirror-port anyway.
.
Víctor Cespón
Honored Contributor

Re: How to disable "write cache mirroring" on EVA storage?

Hi, just to confirm, I tried it on two EVA GL, one with firmware 3110 and another with 4100.
In Active/Active mode, it's not possible to disable.
There's the option in Active/Passive mode when creating an vdisk or it can be changed using SSSU.