Friday, July 9, 2010

ARC Cache revisited

As we move more and more active mailboxes onto our OpenStorage box, it's time to have a look at the ARC cache.

If you remember, I already blogged a while ago about the ARC. At that time we had only inactive mailboxes, with almost no access other than incoming mails.

This is how it looks with active mailboxes:














I've colored all the hits. As you can see, there is a huge amount of metadata hits and prefetched metadata hits. You can also see some data hits and prefetched data hits.

We're now constantly adding more and more mailboxes to the system, resulting in more and more metadata. As the amount of data grows L2ARC will become more important. Stay tuned for a blog entry about how the L2ARC behaves...

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