On 10/24/2016 04:51 AM, mark wrote:> Absolutely add nobarrier, and see what happens.Using "nobarrier" might increase overall write throughput, but it removes an important integrity feature, increasing the risk of filesystem corruption on power loss. I wouldn't recommend doing that unless your system is on a UPS, and you've tested and verified that it will perform an orderly shutdown when the UPS is on battery power and its charge is low.
Gordon Messmer wrote:> On 10/24/2016 04:51 AM, mark wrote: >> Absolutely add nobarrier, and see what happens. > > Using "nobarrier" might increase overall write throughput, but it > removes an important integrity feature, increasing the risk of > filesystem corruption on power loss. I wouldn't recommend doing that > unless your system is on a UPS, and you've tested and verified that it > will perform an orderly shutdown when the UPS is on battery power and > its charge is low. >As I noted in my original repost, that it needs to be on a UPS, and to repeat myself, untaring a 107MB tarfile on an xfs filesystem mounted over NFS, it was ->seven minutes<-, 100% repeatable, while after we added nobarrier and remounted it, it was about ->40 seconds<-. That's *hugely* significant. mark
On 10/24/2016 07:29 AM, m.roth at 5-cent.us wrote:> As I noted in my original repost, that it needs to be on a UPSAh. I see that now. Still, may I suggest that whenever we recommend remedies that eliminate reliability measures, such as mounting with "nobarrier", we also repeat caveats so that users who find these conversations in search results later don't miss them? I think that's important to note that the system should be on a UPS, *and* that it has been verified that the system will perform an orderly shut-down before the UPS loses charge. "nobarrier" shouldn't be used without performing such a test.