On Mon, 2006-10-30 at 13:16 -0500, Lon Hohberger wrote: > 1U APC switches are less expensive and have SNMP capabilities, but to > feed NSPF power to a cluster, you would need at least two of them; the > APC 9225 switches only have one power rail. This means if you trip over > the switch's power cable, all cluster nodes powered by the APC unit die. > APC switches can also often be daisy chained together, but our agents do > not generally support the configuration. (I think the CVS version does > on the most recent hardware, but probably not on the 9225... Jim?) > > Ex: single power supplies connected to typical APC devices: > > power1 power2 > | | > server A APC1 APC2 server B > +----1 1-----+ > > Ex: dual power supplies connected to typical APC devices: > > power1 > | > server A APC1 server B > | +----1 | | > | 2-------------+ | > | | > | APC2 | > +-------------------1 | > 2------------+ > | > power2 > > > > The WTI IPS800 switches above have two power rails with 4 ports each. > The CE version is 208v; the non-CE is 110~120v, otherwise, they're the > same. They cost more per unit than the 9225. You can control dual > power supplies on separate rails, giving you NSPF as far as power-cords > are concerned. If you pull one of the power sources, the power switch > is still accessible and fencing will still work, because the internal > electronics can run off of either power rail. (I'm not sure what the > fault mode is if the electronics fail, though; I *think* it leaves the > ports in their current states; contact WTI if you have questions about > this). > > Ex: dual power supplies connected to typical WTI devices: > > power1 > | > server A IPS server B > +----1 | > === | > 5----+ > | > power2 > > Ex: dual power supplies connected to typical WTI devices: > > power1 > | > server A IPS server B > | +----1 | | > | 2----+ | > | === | > +-----------5 | > 6-----------+ > | > power2 > > >From a reliability standpoint, APC and WTI both make extremely reliable > devices. I've never had any switch from either vendor go bonkers on me. > > Not to state the opinion of any company I may or may not be employed by > or affiliated with, I personally generally prefer the WTI devices over > APC devices because of: > > (a) Design - I *totally* dig the dual power rail configuration. It has > higher power capacity per switch (30A, 15A per rail/4 ports), as well > two power sources (note: it's *two* rails; not a single, redundant rail, > even though the switch control electronics can run off of either rail) > > (b) Firmware revisions on APC devices have broken fencing agents on more > than one occasion. (Though, this isn't so much a problem with the newer > APC SNMP fencing agents, but I don't like setting up SNMP...). > > Jim Parsons (current fencing maintainer) has differing opinions on the > matter; I believe he prefers APC units over WTI units. > > -- Lon Thanks Lon for all the superb informations. Due to support availability, I prefer APC over WTI. It's just that APC has office in Malaysia and provide support locally. Now the problem is; I'm not be able to use the APC9225 model due to output voltage issue. APC9225 uses 120V while we in Malaysia use 220-240V/50Hz. APC suggest me to use another model, APC7921[1]. Nevertheless APC7921 is not included in Red Hat documentation as a preferred (supported???) model. So, any idea on this issue? Is Red Hat going to support me even though I'm using unrecommended model? I have 2 servers to be clustered with a single service. Is it ok to use 1 network power switch, or is it recommended 2 power switches (1 power switch per server)? [1] http://www.apc.com/resource/include/techspec_index.cfm? base_sku=AP7921 [2] http://www.redhat.com/docs/manuals/csgfs/browse/rh-cs-en/s1- hardware-clustertable.html#TBL-HARDWARE-FENCEDEVS -- Regards, +--------------------------------+ | Mohd Irwan Jamaluddin | | ## System Engineer, | | (o_ Magnifix Sdn. Bhd. | | //\ Tel: +603 42705073 | | V_/_ Fax: +603 42701960 | | http://www.magnifix.com/ | +--------------------------------+ | "Every successful side needs | | unsung heroes" - fcbayern.de | +--------------------------------+ -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
