On 04/21/2014 12:40 AM, Micky wrote: > Ok, this is pretty odd. I have setup a few GZs with little to no activity, > and I am seeing a consistent write latency of 15 to 20 microseconds. > > # vfsstat -IMzZ 2 3 > r/i w/i Mr/i Mw/i ractv wactv read_t writ_t %r %w d/i del_t zone > 151.0 6.0 0.3 0.0 0.0 0.0 1.8 15.6 0 0 0.0 0.0 > global (0) > > This is 20131128T230213Z, loaded with default ::zfs_params. > > Am I victim of some throttling bug somewhere?
You'll note that the del/i column is zero. That means that you're not seeing any delays. 15 to 20 microseconds seems pretty good. It means that all your reads are hitting in the ARC and all your writes are asynchronous. You're not hitting your disks at all. If you were, I'd expect to start seeing times in milliseconds. Can you describe what behavior you were expecting to see here that makes this seem odd? Of course, averages can be misleading, you should certainly take break things down more discretely and consider looking at the zone_vfs kstat module or with DTrace. Robert ------------------------------------------- smartos-discuss Archives: https://www.listbox.com/member/archive/184463/=now RSS Feed: https://www.listbox.com/member/archive/rss/184463/25769125-55cfbc00 Modify Your Subscription: https://www.listbox.com/member/?member_id=25769125&id_secret=25769125-7688e9fb Powered by Listbox: http://www.listbox.com
