eho@clarity.princeton.edu (Eric Ho) (07/11/90)
Has anyone out there been using those UPS (Uninterruptible power system) boxes for Sun servers ? In particular, I want to get opinions about the UPS boxes from Elgar (in San Diego) -- e.g. how reliable they're for Sun servers (they claim that their boxes will nwall(8) messages out to users upon power outage and then do an shutdown(8) within 10mins if the power doesn't come back up and when the power comes back up, it'll reboot the server and recharge its batteries again -- it uses up a serial port which connects the server to the UPS box and some kernel changes). I've 2 servers (3/180 + 4/280) -- each has 2 SMD drives (one has 2 eagles, and one has 1 eagle + 1 hitachi 892meg). One has a 1/2-inch tape drive and one as a 1/4-inch tape drive. Also, one has a 16meg ram expansion from clearpoint and an ALM-1 board. It'll be great if someone can share some of their experiences using this kind of boxes on Sun server equipments. Thanks in advance. Eric Ho Princeton University eho@clarity.princeton.edu
paul%ppgbms@uunet.uu.net (Paul Evan Matz) (07/18/90)
In article <9852@brazos.Rice.edu> eho@clarity.princeton.edu (Eric Ho) writes: > >Has anyone out there been using those UPS (Uninterruptible power system) >boxes for Sun servers ? In particular, I want to get opinions about the >UPS boxes from Elgar (in San Diego)... So far, the only UPS we've found that will work well with SunOS is the IPS 400 + 600 from Elgar (800-854-2213). You can buy "Unisafe" for SunOS ($99) which is a set of sh scripts that monitor the state of the UPS via a serial port, and shutdown the Sun in the case of a power failure. The price of the UPS; something like $500-600. One unique feature that the Elgar has is the ability to shutoff its UPS output power to the Sun once it has halted. This is very handy when the power failures are frequent or long. (The key here is that the UPS has a built-in delay circuit which waits for 20 seconds after being signaled before it shuts off its output power; The Sun signals, then halts. This gives it 20 seconds to halt and flush. Without this feature, it is difficult to make sure the disk is flushed while under software control. Once the Sun has halted, it can't signal the UPS to shutoff. Your basic catch-22). Powering a monitor is problematic for most UPS, this one included. The problem is not power usage, by peak current. A 16" color monitor might use as much as 3 Amps peak (although only about 100 Watts average); That coupled with the Sun will amount to more then the max. for most UPSs (3.3amps max). Therefore, don't plan on powering you monitor. This will usually not be a problem for servers. Power just a SPARCStation 1 w/ 2 104M disks, the projected power backup time is something like 1.5 hours. I ran it for about 20 minutes without any noticable battery discharge (as shown by a battery capacity bar graph display on the UPS's front panel). The UPS monitor daemon process senses when power goes down by being blocked on a read of the tty; The UPS asserts CD when power goes down, thereby unblocking the daemon, who proceeds to start a countdown. (There's no connection to the Receive data pin). There are various configurable parameters that define how long the daemon ignores a power outage, how long it waits after it notifies users to logout and before it starts to kill off processes, etc. The daemon is built out of scripts, so it is easy to checkout and modify if you need to, although I think they could use a little more work. When it is finally time to shut off the UPS, the script signals the UPS by writing a file of all zeros out to the tty (the Transit Data pin is connected to the UPS). Then, unless the AC power comes back on, the UPS shuts off power to the Sun in 20 seconds. The script hammers as many processes as it can (including itself, by the way), sleeps for 20 seconds and then reboots (so if the power does come back on, the machine won't be sitting there halted). There is a race condition where, depending on the spacing of multiple power outages, you can get your power shut off during a reboot. (This is one of the things that need to be fixed in that daemon script). Another problem with the Elgar software is its installation instructions. On a SPARCstation, there are a few details which are omitted, like setting carrier-detect-ignore to false, and adding the serial port to gettytab. I think they are working on fixing this, though. I have no real info on reliability. So far, so good. The support from Elgar (Tod Fox) is very good. Hope this is of interest.
shenkin@cunixf.cc.columbia.edu (Peter S. Shenkin) (07/21/90)
I'm trying to sort through the maze of vendors' claims in order to pick a UPS to protect a Silicon Graphics Personal Iris (PI). I am hoping that someone out there more knowledgable than I can help me out. I will summarize to the above newsgroups. The following is in fact a summary of what I've learned about these devices so far, but the purpose of this posting is to find out more. The PI has a power rating of roughly 1kVA; however, I am looking at units in the 2-5kVA range for the sake of future expansion. The 1990 Science "Guide to Biotechnology Products and Instruments" (Science, vol 247, 23 March 1990, Part II) lists 19 suppliers, though probably there are only about 5 manufacturers and the others re-sell or OEM these units. So far I've spoken to the following companies: Best: (800) 356-5794 Clary: (818) 287-6111 Personal Computer Tools : (800) 767-6728 Shape Electronics: (800) 367-5811 Anixter Electronics: (800) 323-8166 Elgar Electronics: (800) 733-5427 Lambda and Liebert are also listed, and I want to talk to them. Now, I gather there are "on-line" units, and "standby" units; standby units are cheaper, and also seem to come in lower power ratings. Elgar sells a 1.5kVA standby unit for $1875, and then jumps to a 3kVA on-line unit for $6145. A standby unit kicks in only when the power goes down, which has two implications: (1) there is a time-lag during which you don't have power. Elgar quotes 4ms for their 1.5kVA unit. (2) you get no (or little) surge protection and power conditioning from the unit. The on-line units are, theoretically at least, supplying power all the time, and are said to give good power conditioning. So my FIRST QUESTION is: for the intended use, is this a red herring? I have been assuming I need an on-line unit, but is a 4ms delay likely to give problems? (I note that using 60 Hz power, 4 ms is a bit less than 1/4 of a cycle.) In fact, I probably want a unit with larger capacity anyway, but the answer to this question would still be good to know, and it comes up again, just below. Of the so-called on-line units, Best has the best list prices. Examples: * Best: 2.1kVA, $2995; 3.1kVA, $3695. * Anixter: 2kVA, $4335. Elgar: 3kVA, $6145. * Clary: 2kVA, $5590; 3kVA, $6550. * = offer some academic discount; range is 5-15%. However, it seems that there are on-line units, then again there are on-line units. Best's inverter doesn't always run; they've got a big ferroresonant transformer that ballasts the load while the inverter kicks in. Clary emphasizes that their inverter always runs, and therefore that their unit is "really" on-line at all times. On the other hand, Best's transformer is bound to give excellent power-conditioning, or so it would seem to me, as should Clary's unit. Best presents their way of doing thing as a virtue: since the inverter doesn't always run, the UPS is cheaper to operate, and will also last longer. Clary also says that only their unit meets UL-544 for low leakage current, which qualifies the unit for use in surgery. I'm confused about this; where is current going to leak to? Is this a ground-leak, or what? It seems to me that no matter what the power supply does, the load is only going to draw what it needs. Clearly, I'm confused. So my SECOND QUESTION is whether the ballast route to making a unit "on-line" as "good" as the inverter-always-on route? That is, perhaps instead of a two way classification (standby and on-line), we should have a three-way classification: standby (eg 4ms delay) ballasted standby (eg, Best) "true" on-line (eg, Clary). So the question is: which one should I get? :-) Is the ballasted unit really more like a standby, or more like a true on-line? and where is the critical breakpoint for my application? Has anyone heard of a ballasted unit (eg, Best) failing in a computational application? My THIRD QUESTION is: can you clarify my confusion about UL-544 and low leakage current? (a) What does it mean, and (b) Do I need it? Now I simply comment about battery capacity. All the units mentioned will run at full load for at least 10 minutes; some units run longer. If instead you run at half load, you more than double your backup time. My own purpose is to protect my equipment, not to continue operations uninterrupted for significant lengths of time; therefore 10 minutes is fine; it's plenty of time for an orderly shutdown of a workstation. Which brings us to our next topic: Computer interface. Just about all of these machines (exception: Elgar on-line units) are equipped with RS-232 interfaces which signal the state of the UPS. For example, some line goes from low to high when the external power has failed, and the machine is running on battery power. A setuid root program that monitors the port can then bring the machine down if this happens, or if the condition persists more than x minutes, or when the UPS signals only five minutes backup power remaining, or whatever. For some of these units the RS-232 is bundled, and for some it is an extra-cost option (Clary: $200). Some of the vendors supply software to monitor the port (Elgar: $250-300; Best: $125) but others (Clary) don't have UNIX drivers. Some of the vendors actually issue unix-flavor-specific drivers (eg, SunOS), as well as generic UNIX drivers. The Elgar standby units have the following feature: the UPS can be set to turn itself off after it brings the computer down. Some users tout this feature. QUESTION FOUR: why do you care whether or not the UPS turns itself off, once it's safely brought the machine down? I have heard that there is a company (maybe Apunix?) that OEMs some UPS, and also supplies kernel mods, at least for SunOS, that allow the UPS to reboot the machine when the power comes on again. I don't feel I need this feature, and am mentioning it for completeness. But I do have a final question: QUESTION FIVE: Do you have personal experience with any of these power supplies, or with their competitors? If so, I'd appreciate it if you'd share your experiences, likes, dislikes. Thanks, Peter Shenkin, Department of Chemistry, Barnard College, New York, NY 10027 (212)854-1418 shenkin@cunixc.cc.columbia.edu(Internet) shenkin@cunixc(Bitnet