[horde] Guidance on SQL vs. NoSQL storage

[Ralf Lang]

Hi

Am 12.03.21 um 23:17 schrieb Nels Lindquist:
> Hi, all.
>
> We recently added a node to our Horde access server, and I figured I'd
> take the opportunity to try out MongoDB as a NoSQL storage method for
> shared data across the cluster.
>
> Unfortunately it hugely spiked the load on the server, and I ended up
> backing out the config and reverting to PostgreSQL for the shared
> storage.
>
> Is there any guidance or recommendations for the kinds of data it
> might be appropriate to consider using one over the other? eg.
> ActiveSync caching vs. IMAP caching vs. session data, preferences, etc.?
>
>
Hi Nels,

it depends on what you already have in your infrastructure and what you
can administrate well with your resources available or can consume as a
service offering.

I use a lazily-persistent redis key/value store as my preferred
Hashtable (DHT) provider in most installations. It used to be memcache
but I find redis more easily scaleable in my use cases.
In turn, I use DHT as my cache. It used to be HashTable as "in memory"
cache and SQL als fallback cache, but I found this not beneficial.

I also use DHT via redis for session handler in multi node installations.

I want to reduce DB writes for data I don't really care about / can
afford to be lost on crashes. On the other hand, any memory spent on a
DHT is memory you could also spend on SQL database caches. Any tangible
benefit comes only with scale.

Now where does a real NoSQL DB like Mongo shine?

I find it useful for any larger blobs which do not need to be searched.
This would be Virtual Filesystem (Vfs) items. Note there are different
Horde Vfs settings for Horde and the applications. Applications should
have "use horde defaults" as an option or default.

The imp (webmail) compose log also makes sense in mongo, but it's not a
major i/o driver in my cases.

In the end, all performance driven changes need validation.

Hope that helps.

-- 
Ralf Lang
Linux Consultant / Developer
Tel.: +49-170-6381563
Mail: lang at b1-systems.de
B1 Systems GmbH
Osterfeldstraße 7 / 85088 Vohburg / http://www.b1-systems.de
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