Booting from Compact Flash

[jasonsRX7]

Originally posted by: Paperlantern
what about ram drives? i've only heard about them, or are they essentially compact flash. I wouldnt think so, since RAM is unlimited read writes, and direct access memory. They have battery back ups to keep info, but if the computer are going to be used in server type scenarios they wouldnt be turned off ANYWAY. jsut a thought

You could actually install the OS to a CF card, and then at boot time create a ram drive and copy the image there. That would reduce by far the numer of reads/writes to the CF and squid performance would be great, however the downside to that would be the amount of ram required and the long boot time to read the image from the CF.

The other thing you might be referring to as a ram drive is a Solid State hard drive. They're different than compact flash. That was the first thing I thought of when I first started on this project, but I had not checked the prices in years, and assumed they were still several thousand dollars. However, check this out.

Simpletech 640mb Solid State drive

It's only $400 for a 640mb drive. That might not leave much room for caching, but it'll be sufficient, I think.

 

[Jeff7181]

Maybe check into this...

 

[jasonsRX7]

Originally posted by: mechBgon

As for the topic at hand, you say you want reliability and then propose doing something that has not been extensively tested. I suggest a tried-&-true Cheetah 15k.3, which puts out no more heat than a Seagate IDE drive, and is warranted for 5 years of 24/7 usage in a server (meaning, heavy usage).

(let's see if my advice is useless too )

I do want reliability, but I didn't know if this sort of thing has been extensively tested or not. That's why I asked. I certainly haven't ever tried to do it.

Yeah, I trust SCSI drives in all our real servers but they all have very adequate cooling. I've never run one in a sealed enclosure with almost no ventilation, however, so I'm not sure how well it would perform there. Also, it would be physically impossible to install a scsi controller in the ITX formfactor case I want to use, as the only available slot would be filled by the 2nd nic.

Nah, your advice isn't crap, its appreciated.... Dug's comment just struck me wrong I suppose, like he thought the whole idea was too far fetched and I'd be better off just putting them somewhere else. Anyway, I added up above that it was rude of me to say that...

 

[Jeff7181]

Out of curiosity, what type of processor are you planning on using?

 

[jasonsRX7]

Originally posted by: Jeff7181
Maybe check into this...

I came across those, too, when I was googling for solid state drives. I couldn't find it available at any of our vendors sites, so I'll have to call some reps in the morning and see what kind of prices we're looking at. I'd definately like to have at least a gb if possible, to leave around 500mb for squid.

These drives are made for just such an application and the prices used to be so high, but it looks like they've come down a lot now. $400 is a lot for only 640mb but the OS will only use up around 330, so that'll leave me a bit for logging and cache if I can only manage the 640mb drives within my budget.

What I'll do is get some prices for these drives in the morning, then I'll post some links to all the hardware so you can all get an idea of the full system specs. Maybe it'll be of use to some other people as well.

 

[imported_Pablo]

really interesting thread.... TTT

 

[jasonsRX7]

Originally posted by: Jeff7181
Out of curiosity, what type of processor are you planning on using?

Fanless, and small.
this board
I know, I know, I'm wanting something reliable and it's a VIA system. Reliable and VIA don't go in the same sentence, but that's another story. However, these systems are designed to be built into appliance boxes which they have been with much success so I feel pretty safe using them.

mini-itx.com

I'll post the rest of the system, including the enclosures in the morning, but for now I've gotta get to bed...

 

[jasonsRX7]

Ok, here's all the components

Case
Memory
System board
Solid state drive
Enclosure
2nd nic

And the OS
Mandrake Multi Network Firewall

If you've never tried MNF before, it is a really slick product. We've got it running here in a simulated environment on a Celeron 366 with 64mb test system and even under a moderate load, it remains very responsive.

You can even enable content filtering on squid to prevent access to inappropriate sites, if need be. And using SARG you can generate detailed reports of traffic by individual users.

I'm still waiting on call backs from my vendors for pricing on some more solid state drives, but what I have listed should do the trick. Any suggestions on the parts or any other ideas?

Edit: Just got a call back on this 1gb solid state drive. Our pricing puts it well below $600, which is reasonable I think.

 

[MysticLlama]

It sounds to me like the solid state would be the best bet, they are much cheaper than they used to be for sure.

Are there any comparisons of those to regular hard drives? I know that the 2GB ones I've seen blow everything away, but on the other hand, those are still a few thousand dollars. These might be sacrificing performance for price. In this situation it may not matter, but it's still something to watch out for.

Also, if you were planning on running it on a 640-1GB solid state drive, you could very well do the CF "ROM" and RAM drive option for near the same price. It's something to think about, as that's the idea used on high end routers and firewalls all the time, and even some new PocketPCs (hold the OS in ROM, but expand it to RAM on boot and run it from there), and they still boot up right quick.

Also, the other thing I picked up on was the OS eating 330mb. Is that really needed? That seems like an awful lot of space for an "appliance" device, especially one that *nix based. The Windows2k Appliance Kit doesn't even take that much space I don't think and it's a superset of Win2k (all the same stuff plus some as far as I can tell). Do your VPN boxes really need a webserver, fileserver, print server, etc.? It's also better for security to remove that sort of stuff if it's not being used (even if it is turned off)

Just some more thoughts for ya.

 

[jasonsRX7]

Mystic,

I haven't seen any direct comparisons between the solid state drives and a conventional drive, but my sales rep did give me the numbers. I want to say they had around 10MBps read, and 6MBps write speed. More than enough performance for this...

Other than performance, can you think of any advantages to going the ROM/RAM drive route over the solid state route? I'm not sure if the performance difference of a ram dive is worth the added configuration, but maybe there's something else I'm not thinking of.

330mb is a little big for just a firewall, isn't it? Well, 30+ mb is the swap file... There are a few other services that I want running, which I've mentioned already, and the configuration is web based so it does have to have a web service running. There's no ftp, no Samba, no print server... it doesn't even give you an option of packages to install. I'll look into it and see if there is a way to slim it down any. But you're right, you would think it could be much smaller than that.

 

[Pauli]

jasonsRX7, you're getting some very good ideas here, but I just have to wonder that your goals are perhaps set a bit too high for a more or less off-the-shelf, standard, PC components. Your requirements are VERY HIGH, I mean, c'mon, a PC that will need to run 5 years with little or no maintenance? As far as I know, this PC just does not exist anywhere, at any price. There are so many things that could go wrong - power supply, RAM, network card, processor...and in a harsh operating environment no less. I suspect your storage subsystem will be the least of your problems. Good luck and keep us updated on the progress.

 

[DaveSimmons]

Just a point of concern, SimpleTech no longer lists any actual drive models (2.5" or 3.5") on their website so these drives might be an orphaned / discontinued product. Also, the tiny bit of product info they list says they use flash memory and doesn't list what (if anything) they do to get around the max rewrites limitation. Based on the price-point I'd be surprised if the devices use the obvious workaround of (battery + DRAM + flash) and writing changes only at reset or powerdown.

If it's just essentially a CF card in a disk package, then you still need the ramdisk for cache.

 

[MysticLlama]

Yeah, those numbers do seem not too bad.

The only big improvement the RAM/ROM thing would give you is that you could very easily do a new configuration without having to fiddle with it whatsoever, as long as you kept all of your remote boxes the same.

I'm sure that if you wanted to update it, you could easily enough find someone near the site that could swap out a CF card. That way you could completely replace the config without touching the production one at all, if it didn't work, swap the old one back in. Also, RAM would of course be faster than anything else available, I'm sure that's why most top firewalls and routers store their OS there.

I'm still amazed at the size with no FTP, no Samba, etc. The entire PIX fits in a 16mb ROM, and even though it might not be AS capable, it still does a lot of what you want to do. It should be like 100MB if that, but I realize you're using a tuned distro and you may not be able to remove stuff, but it's something to keep taking a look at.

Also, the power supply could be an issue, I would assume it has a fan, which leads to a dust/mechanical problem. Encasing it in some sort of enclosure would of course be the best route, but that's another thing that you don't have with a dedicated appliance.

You could though, maybe take the covers off of the power supplies, and rig the enclosure so it gets "enough" air without a fan, but I don't know if you'd want to go there with this project.

Another thing, I know you don't want to be tied to the central office for Internet access, but kick around the idea of moving logs and such to there after they get to be a certain size, this way if something does break, or it crashes while running on RAM you still have them backed up for a while, and also, if you're using the solid state, you won't have to worry so much about how much space it has.

 

[jasonsRX7]

Originally posted by: Pauli
jasonsRX7, you're getting some very good ideas here, but I just have to wonder that your goals are perhaps set a bit too high for a more or less off-the-shelf, standard, PC components. Your requirements are VERY HIGH, I mean, c'mon, a PC that will need to run 5 years with little or no maintenance? As far as I know, this PC just does not exist anywhere, at any price. There are so many things that could go wrong - power supply, RAM, network card, processor...and in a harsh operating environment no less. I suspect your storage subsystem will be the least of your problems. Good luck and keep us updated on the progress.

You're right, I do have very high hopes for the systems but I think (hope ) my goals are achievable. The things you mentioned that could go bad (power supply, ram, processor) could also go bad in a dedicated device like a PIX or Sonicwall. There's no getting around that. Even if I were to go the simple straightforward route and buy an off the shelf device, I'd still have to mount most of them in an enclosure.

Believe it or not, we still have some old 386s that are out in some farms that are still running the same old DOS app they've always run and are doing just fine Now how's that for getting your money's worth?

I'll definately post again once I decide what to buy. Even though I do it for a living, I'm still as much an enthusiast/hobbiest as anyone else, so I'm looking forward to the fun as well as the function of building these systems.

 

[jasonsRX7]

Originally posted by: DaveSimmons
Just a point of concern, SimpleTech no longer lists any actual drive models (2.5" or 3.5") on their website so these drives might be an orphaned / discontinued product. Also, the tiny bit of product info they list says they use flash memory and doesn't list what (if anything) they do to get around the max rewrites limitation. Based on the price-point I'd be surprised if the devices use the obvious workaround of (battery + DRAM + flash) and writing changes only at reset or powerdown.

If it's just essentially a CF card in a disk package, then you still need the ramdisk for cache.

That's a really good concern and I'll have to register an account with Simpletech to read their PDFs for some more info. Their drives are listed under industrial products and you have to register with them to see the spec sheets. The SimpleTech website kind of made me wary, but the sales rep ensures me they are readily available, in channel products. We'll see...

 

[jasonsRX7]

Originally posted by: MysticLlama
I'm sure that if you wanted to update it, you could easily enough find someone near the site that could swap out a CF card.

That would be really handy. If something went wrong with the configuration, they could have a backup CF on site to swap out and get back online in no time. I'll determine the additional costs involved...

I realize you're using a tuned distro and you may not be able to remove stuff, but it's something to keep taking a look at.

I'll throw this around in the mandrake forums (if there are any, I haven't looked). I'm sure something can be done to slim it down, without breaking the necessary dependancies.

Also, the power supply could be an issue, I would assume it has a fan, which leads to a dust/mechanical problem. Encasing it in some sort of enclosure would of course be the best route, but that's another thing that you don't have with a dedicated appliance.

Ahh, the power supply is one of the most beautiful things of all. The case uses an external AC power supply, much like you'd find on a SOHO switch, router, or similar device. We could have plenty of spares available at each site, and they could swap them out easily and never have to open a case. Take a look at the last picture here.

kick around the idea of moving logs and such to there after they get to be a certain size, this way if something does break, or it crashes while running on RAM you still have them backed up for a while, and also, if you're using the solid state, you won't have to worry so much about how much space it has.

True... I'll definately end up doing this.

Thanks for all the help so far, everyone... It's really going to make sure I've covered all the bases.

 

[MysticLlama]

Ooohh, I dig that external power supply, though I do have one question for it... how does it provide the different voltages?

It must have some sort of transformer in the front where the wiring comes out, though I'd imagine that it'd be much smaller and have way less heat going from 12v to 5v then from 115v to 12/5v.

Very cool solution for keeping the uneeded heat out of the case though, and I hardly ever see bricks like that go bad.