On 16. sep. 2011, at 16:18, free...@top-consulting.net wrote:

>  Got a measly 74MB/sec.

You can't ask for advice, get it, do something completely different, and then 
complain that it didn't work. 

Neither can you ask people to donate their time, if you won't spend yours. 

In other words: if you won't listen, there's no point in us talking. 

However:

Don't disable ZIL. Just don't. It's not the way to go. If you want to know why, 
google will help. 

Also, you're making some assumptions, such as the ZIL being bad for 
performance. That's not always the case. ZIL-writes are a rather nice load for 
spinning metal storage. Even if you write through cache, that can give you a 
boost on your real world workload. 

Which brings us to the third bit. You're benchmarking, not trying real world 
loads. That's the load you'll have to worry about, and it's the load zfs shines 
at. 

Thanks to the ZIL (the thing you're trying to kill, remember?) you can convert 
seek heavy writes to sequential zil-writes, freeing up disk bandwith for 
concurrent reads. 

If you want to test before spending money, try what Svein said. Set up a small 
logical volume (preferrably smaller than your controller cache, if it's large 
enough), then try that as a dedicated zil-device. 

Never tried that, but worth a shot. 

Terje_______________________________________________
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