On 03/18/2011 06:36 AM, Rajagopal Swaminathan wrote: > Greetings, > > On 3/17/11, bergman@xxxxxxxxxxxx <bergman@xxxxxxxxxxxx> wrote: >> The pithy ruminations from Digimer <linux@xxxxxxxxxxx> on " >> Tripp Lite switched PDU fence agent; exists?" were: >> >> >> >> Finally, I'd like to warn people away from using the TrippLite PDU model >> PDUMH15ATNET as a fencing device. While it seems to have nice features, it >> has >> a design choice that is a serious problem with fencing--when a command is >> given to power down an outlet, there is a "random" delay (observed to be >> about 17 to 35 seconds) before that command is executed. This has been >> acknowledged by TrippLite support as a design choice, with no option or >> setting >> to override this behavior. >> > > This "powerfence" should come nowhere near a production cluster. > > Such randomness can play havoc in the predictability of availability: > Just think two of those strips (A,B) used for each of the redundant > power inputs and they not being switched off together. can get _very_ > messy. > > Just my 2paise > > Regards, > > Rajagopal At the end of the day, I think the argument for or against a device's use should be secondary to it being supported. It's difficult to predict why a user may want to use a given piece of hardware. I'm hoping that adequate warnings in the docs to potential drawbacks will suffice. As for this specific device, I'd not seen a review of it when I ordered it. I plan to write an amateur review and I will specifically test for these issues. If I can not find a safe way around queued fence calls, then I will certainly include that in the review. That should hopefully help steer people away from using this device, should the delay be a show-stopper for them. Cheers -- Digimer E-Mail: digimer@xxxxxxxxxxx AN!Whitepapers: http://alteeve.com Node Assassin: http://nodeassassin.org -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
