ZFS: How to enable cache and logs.

[Šimun Mikecin]

On 12. svi. 2011., at 08:44, Daniel Kalchev wrote:

> On 12.05.11 05:26, Danny Carroll wrote:
>> 
>>  - Don't use SSD for the Log device.  Write speed tends to be a problem.
> It all depends on your usage. You need to experiment, unfortunately.

What is the alternative for log devices if you are not using SSD?
Rotating hard drives?

AFAIK, two factors define the speed of log device: write transfer rate and write latency.
You will not find a rotating hard drive that has a write latency anything near the write latency of even a slowest SSD you can find on the market.
On the other hand, only a very few rotating hard drives have a write transfer rate that can be compared to SSD's.