Ok. Thanks again!

need to destroy existing fast cache config before you remove those drives.

Thank you so much Dynamox! It's good to know that we call pull out and replace the drives without issue. I will schedule this during activity during our maintenance window.

Thanks again!

Admingirl

Fast cache will need to be rebuild so you might want to do it during low io times but other than that you should not be needing downtime.

I would double-check with EMC and the procedure generator

I think if you increase the Fast Cache size we need more memory which means at least the SP has to rebooted

Why would an SP reboot be required? You can adjust the memory without rebooting the SPs.

Ok – fair enough

No reboot is needed...

but as Dynamox stated earlier the first step is to destroy the original Fast Cache, this operation requires all data in the Fast Cahce to be written to disk, this can take a long time depending on the workload of the array and the numbers of disk and speed of same....

We  have seen it take up to 18 hours to complete....remember that in this period of time you have no Fast cache at all on the array, and this can cause a serious degradation of performance...the system will of course still be working, but the SSD used for Fast Cache is just not serving IO, and are adding to the load on the normal disk due to the data being flushed...

after this is done, it is just to enable Fast Cache using the new disks, remember to use the correct disk, would recommend creating the new Cache via CLI...

It is correct that a larger Fast Cache required more memory, but this can be changed without rebooting SP

Rainer_EMC wrote: I would double-check with EMC and the procedure generator I think if you increase the Fast Cache size we need more memory which means at least the SP has to rebooted

if that was the case then when you first set up Fast Cache it would require SP reboot ..which i know for a fact it does not.