Possible to decrease RAM quota?


#1

I’ve got a bucket set for full eviction and I’d like to test out other smaller memory configurations without having to delete the bucket and reload all the data since it’s a considerable amount. I’ve been able to find a plethora of information regarding increasing the size but have come up empty on decreasing the size. Is it even possible?


#2

Yes, it’s possible. You can just change the RAM per Node for a bucket, e.g.


#3

Thanks for the reply. I should have been more detailed. That seems to work
only when the current RAM usage is below the intended level. I was looking
for a way to effectively truncate the cache via something like LRU. For
instance I’ve got the current quota set to 12GB, usage is 9GB but I would
like to try 6GB. When I do that now, I get a message saying “RAM quota
cannot be set below current usage.”

Thanks again


#4

Ah, understood. I don’t think that’s possible, at least through the web UI. The only workaround I could suggest is to use cbbackup to take a copy of the bucket, create a new bucket with the reduced quota, and then use cbrestore to insert your backup. I’ve never tried inserting a backup into a too-small bucket, so can’t say that it will definitely work.

The backup documentation is here: http://docs.couchbase.com/admin/admin/Tasks/backup-cbbackup.html


#5

I’ve got the current quota set to 12GB, usage is 9GB but I would like to try 6GB.

@kirkbcb That is possible you just have to do it in a few steps you cannot jump straight down to 6GB. First you would have to change the bucket quote to just above 9GB and let the Cluster eject the items from memory down to the low watermark which is 75% of the quote. Then move it down again until you reach 6GB.