Date: Tue, 21 Aug 2001 18:01:22 -0700 (PDT) From: Hodge Podge <nicole@unixgirl.com> To: Michael VanLoon <MichaelV@EDIFECS.COM> Cc: val@picturetrail.com, mike.wentz@3ware.com, freebsd-hardware@freebsd.org, Borja Marcos <borjamar@sarenet.es> Subject: RE: 3ware stuff not ready for heavy duty useage-followup Message-ID: <XFMail.010821180122.nicole@unixgirl.com> In-Reply-To: <36F7B20351634E4FBFFE6C6A216B30D54CAD@ecx1.edifecs.com>
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On 22-Aug-01 Michael VanLoon wrote: > Ignore physics if you want. I tend not to try to bend the laws of reality. > The numbers are in front of you: there are some conceivable situations where > you will over-load your power supply. It may not happen frequently, but it > can happen. Oh I don't doubt that at all. I used to be an engineering technician who had the fun task of taking what engineers said shoudl work.. on paper and making it work.. for real. > As someone else posted, if you're also running all those big fans off this > PS you're loading it further. Not that much, the fans are very efficiant. > You've been lucky in the past. You won't always be lucky. > It's funny how you say you've run these big servers in the past and they > worked all great with off-the shelf power supplies. Our biggest servers > have power supplies in them commonly twice the size of normal desktop > machines, and being proprietary (often redundant), I don't even know how > many watts they are, but you can bet they're more than 300. You might want to check. Quite often they are not. Have you seen the wattage on power suplies in 1 and 2U servers. Pretty damn small. > Note this isn't a SCSI/IDE issue. I'm one of the first people to suggest > you should just be running SCSI with a good hardware RAID controller for > most servers. However the rules remain there: too many disks with too small > a power supply = potential problems and hair-pulling. But you have to admit that something this repeatable on different systems seems damn odd. So far I have not seen one reply from anyone saying.. Yea I have a system like that that works fine. Only people with 4 port units or folks with small capacity drives. And therein is what I am saying. If you use drives that pack the density so high, they then would likely become more suseptable to any anomilies. > I'm honestly surprised people (myself included) are still trying to help you > when you won't take good advice, and bite the heads off people who try to > make suggestions. I'm not biting your head off, and I'm sorry you took it that way. I am mearly showing examples or reason how your reasoning might be wrong or not applicable in this case. I would like to point to 1 example server that has 13 Drives in it, and only 1 300 Watt power supply. http://www.rackable.com/index-productsST.php3?checkit=noflash They have sold quite a few of these units, they beat the snot out of them at Yahoo and Google, BUT they do not use them in RAID 5 or even RAID 10 as I have been. You would think that they would be having power supply issues, but apperantly they have not. This is but one example of why I think the power supply issue is not relevant, but perhaps as I stated in my last email.. perhaps is worth testing, especially by 3ware to make sure users have what is needed to use their card safely. Again I will state, I like the 3ware stuff, I wish I could use the 3ware stuff, I do not think it is a FreeBSD or Driver issue. But, when using RAID 10 or RAID 5 with these newer High Capacity drives, the 3ware card may not have enough error handling yet to be able to work well under heavy usage. Nicole > Good luck. Have fun. > >> From: Hodge Podge [mailto:nicole@unixgirl.com] >> Sent: Tuesday, August 21, 2001 4:48 PM >> >> On 21-Aug-01 Michael VanLoon wrote: >> >> From: Hodge Podge [mailto:nicole@unixgirl.com] >> >> Sent: Monday, August 20, 2001 6:38 PM >> >> >> >> On 20-Aug-01 Michael VanLoon wrote: >> >> > I seriously doubt the average 300W power supply is going >> to reliably >> > power >> >> > your computer and that many disks. You might check into >> trying one of >> > the >> >> > Enermax EG651P power supplies which would supply a much >> more stable >> > amount >> >> > under heavy load. Other high-load power supplies might >> work as well. >> > That >> >> > 400 might be OK, but quality construction is important >> too -- some cheap >> >> > generic 400 might not be any better than the others. >> Check with PC >> > Power >> >> > and Cooling, SuperMicro, etc. for suitable power supplies. >> >> >> >> No, 300 watts is plenty. IDE's do not use as much current >> as SCSI drives >> > and I >> >> have run more scsi drives than that on a 300W Power supply. >> >> >> >> Now I suppose it would depend on the amount of activity >> and the drives >> >> particular sensitivity, but that only makes the case more >> so in some ways. >> > How >> >> much coddling do the IDE's need then? >> > >> > Well yes and no. First it depends how much power your >> system itself is >> > pulling. Don't forget that AMD recommends a minimum of >> 300W power supply >> > for just your average desktop with only one or two drives. >> Intel chips suck >> > up less, but in some cases not significantly less. >> > >> > Now you may be right in some cases. I decided to go look >> at the Maxtor and >> > IBM sites. It seems under peak load, considering >> worst-case (highest >> > electrical running load) on eight drives (I think that was >> your biggest >> > set-up) you get a power draw of: >> > >> > Maxtor DiamondMax Plus 60: >> > 4.80 Amps at 12V >> > 4.40 Amps at 5V >> > >> > IBM 60GXP: >> > 5.36A at 12V >> > 3.92A at 5V >> > >> > These are for average load. I think Maxtor doesn't >> actually print true peak >> > because IBM's is quite a bit higher than these. At peak loads: >> > >> > IBM 60GXP: >> > 16.00A at 12V!! >> > 9.04A at 5V >> > >> > Remember that's 16A for the hard drives alone, not counting >> any other stuff >> > installed in your computer. >> > >> > Someone mentioned having problems with starting the system >> properly. Here's >> > maybe why... look at these spin-up currents: >> > >> > Maxtor DiamondMax Plus 60: >> > 23.60A at 12V!!! >> > 3.44A at 5V >> > >> > IBM 60GXP: >> > 16.00A at 12V!! >> > 6.4A at 5V >> > >> > >> > The quality Enermax power supplies are a good place to look for some >> > guidance on this. Remember that cheap no-name power >> supplies are typically >> > going to handle this worse than well-made ones will. Their >> 300W model >> > (EG301P) has a max output rating of 15A at 12V. This means >> that if all >> > eight drives try to spin up at once, you are over-loading >> the power supply. >> > This can result in startup errors. But even as indicated >> above, if all >> > eight drives are doing full seek traffic all at once, even >> that might push >> > you above the power supply ratings (16A on drives > 15A on >> power supply). >> > >> > And remember this is only the drives -- this doesn't count >> other stuff >> > drawing 12V inside your case. Since the CPU and >> motherboard circuitry use >> > the 3.3V and 5V taps, this likely will not crash your >> machine, but will >> > cause hard drive errors. >> > >> > Even Enermax's biggest power supply, the 550W unit (EG651P) >> is just barely >> > capable of providing enough power for simultaneous spin-up >> of all eight >> > Maxtor drives (23.6A on drives just barely < 24A from PS). >> And that's >> > assuming you don't have more than 0.4A draw on 12V from >> everything else in >> > your system. >> > >> > So your assumption, "300 watts is plenty," doesn't >> necessarily bear itself >> > out. Now if you use things like staggered spin-up, that >> will help alleviate >> > problems with every drive trying to suck down spin-up >> current at the same >> > time, but even with that, your full-load performance is >> just barely over the >> > limit of this particular power supply. Assuming "no, it's >> plenty" without >> > any real proof is an invitation to disaster in my book. >> >> I see.. So what you are saying is then that all those people >> who make and sell >> systems with that many HD's more or less are all asking for trouble? >> That all the scsi systems I have built or seen running >> similiarly and without >> errors anywere near this are just lucky? >> >> So you postulate that if I replace my 400 watt power supply >> with a 400 Watt >> "better" power supply, I will no longer have problems with >> the 3ware card under >> heavy loads? >> I know my boss is not sinking another dime into IDE stuff >> until proven >> safe. So.. Anyone have a power supply they belive will >> handle the load they >> can loan me for testing? I'm game? >> >> What would you say if I told you that the power supply in >> the case was an >> Enermax power supply? >> >> >> >> Nicole >> >> >> >> >> >> >> >> From: Hodge Podge [mailto:nicole@unixgirl.com] >> >> >> Sent: Sunday, August 19, 2001 2:20 PM >> >> >> >> >> >> On 19-Aug-01 Borja Marcos wrote: >> >> >> > On Sunday 19 August 2001 09:10, you wrote: >> >> >> > >> >> >> >> Yup, cables that were supplied by 3ware. In 3 2 or 3 >> >> >> different cases >> >> >> >> and power supplies. Each were 300 or 400 watt power supplies. >> >> >> > >> >> >> > Excuse me for stepping into the discussion, but I >> >> >> think this is an >> >> >> > important issue: Which was the brand of the cases, power >> >> >> supplies and >> >> >> > fans? How much did they cost? Nowadays the choice of a good >> >> >> case and power >> >> >> > supply is as important as the choice of a good cabling, >> >> disks, etc. >> >> >> >> >> >> One of the cases was from Silicon-rax and had a 300 watt >> >> >> power supply. The >> >> >> other cases were from (I think) acmemicro and one had a 300 >> >> >> watt power supply >> >> >> and the other a 400 watt power supply. (don't know the makes >> >> >> of any of the >> >> >> supplies. ******* |\ __ /| (`\ ******* * * | o_o |__ ) ) * * * * // \\ * * * Nicole Harrington | AKA Hodge Podge * ----------------------(((---(((-------------------------------- nicole@unixgirl.com http://www.unixgirl.com/ webmistress@dangermouse.org http://www.dangermouse.org/ nicole@deviantimages.com http://www.deviantimages.com/ -- Powered By Coca-Cola and FreeBSD -- "The world is run by those who show up" -- The Best Place for Your Web Site - www.WebWeaver.net -- ---------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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