On Fri, Jan 19, 2018 at 5:07 PM, Mike Gerdts <[email protected]> wrote:
> The amount of data that can be written in 3 transaction groups is also a > good estimate for how large your slog needs to be. If it is a 12 Gbit/s > SAS device, the device needs to be about 180 GB (1.2 GB/s (accounting for > 8b/10b encoding) * 3 txgs * 5 seconds) to be sure it never overflows to the > log structures on the data disks. By going larger than that, you extend > the life of the slog because the writes will be spread across more cells. > Math is hard. That should be 18 GB. But that doesn't mean you should use a thumb drive. See my other statement about the log vdev needs to be at least as fast as the aggregate speed fo the data disks. Mike ------------------------------------------- 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
