SSD recomendations for ZIL and L2ARC

[Daniel Santos]

Folks,

Could you send me some model recomendations for ZIL and L2ARC sata3 ssds?

 

[Enlightend]

Mind giving some more information on what use scenario you need the devices for?

For general purpose fileserving with decent performance, just about every high speed consumer SSD is sufficient to serve as L2ARC. And in that use case, I'd opt for tons or ram without ZIL SSD's rather then ZIL SSD's, both in terms of price and performance.

If you are looking at a larger system that needs hundreds of GB of fast write cache, various types of SLC drives exist to fit specific needs, but they are pricy as shit. (hence why my preference for more general usage is just using more RAM.)

If you are looking at a system that doesn't need a gigantic amount of write cache, but does need insane IO and write speeds, all sorts of BBU ram drives exist.

So, what is it that you need? Tons of IO, tons of writes, high bandwidth writes, a mix of all of them?

 

[Daniel Santos]

Firstly thank you for the interest Enlightend,

I have a very I/O demanding log correlation application that uses its data directory over NFS and currently no ZIL dedicated device. I don´t know how to measure the current IOPS but I need a ZIL for reducing latency, as NFS is fully syncronous. With my reaching almost its full capacity I am having latency spikes of 10s! I am already working on archiving old data to reduce the swiss cheese effect.

 

[Enlightend]

If that log correlation doesn't use much bandwidth, meaning, you're going at say 10MB/s on gigabit links, then the latency is likely caused by massive I/O and an SSD or battery backed ram drive will likely clear up the high latency quite well.

But much more info is needed to give a good recommendation, could well be an architecture change in how you dump the data can be much better.