Snap Server Boot Image

[blue68f100]

I wish we could iron out what's causing the problems on the 4000's.

[Phoenix32]

Oh yeah. I have built and rebuilt the RAID 5 on these 4000's so many times I see it in my sleep.

Here is a readers digest version of what I can pass on here without writing a book (and it will still be long) on all the information Dave and I have passed back and forth in e-mail.

#1 The 4000's have weak power supplies. The 12V rail is rated at 6A. And let's not forget to take a little of that out for the non hard drive circuitry. Without doing a Power Supply Mod, you are taking a risk of popping your power supply every time you turn the 4000 on if you are using some of the high startup current draw hard drives (large drives). For example, the Seagates (200+) are rated at 2.8A each for start up power. Do the math.

#2 In a Master/Slave RAID 5 configuration, if/when a hard drive fails, the IDE channel companion drive will quite often (majority of the time) orphan itself from the RAID 5 arrary. So now in a 4 drive array, we have one failed drive and one orphaned drive. Guess what that means? Yup, the RAID 5 array is now gone with 2 drives missing. Now it's in data heaven. This is a known problem by Quantum/Adaptec. This is why the revision -003 and -004 4000's use Cable/Select instead of Master/Slave. In a C/S RAID 5 configuration, this problem does not happen (well, it can, but not often). Now there is a catch. Quite a few drives will not work properly with C/S in the 4000 without a modified cable for C/S. Thus, you need to aquire these cables or modify your current cables for this if you have a -001 or -002 model. This involves cutting one lead going to one channel.

#3 Some hard drives, for whatever reason do not work properly, reguardless of the cable type, in C/S mode on a 4000 of any revision. In one test case, I am talking about the commonly used Seagate 250 GB drives. I have a working theory on this, but it is only a theory at this point (see below for this theory if you want to comment on it). But the fact is, I have a 4000 sitting right here with 4 x 250 GB Seagate drives that if you put it in M/S mode works fine, but if you put them in C/S mode, the drives drop in and out with various (mostly superblock) errors, and it does not matter what cables are being used. Why is this a problem? See #2 above.

#4 Revisiting #1 above, the 4000 has a weak power supply. There are a lot of SNAP 4000's out there sitting with dead or malfunctioning power supplies. Unfortunately, replacement power supplies are very hard to come by and can be very expensive (more than the 4000's are worth). I created a Mod to replace the power supply with an AT or ATX power supply, but it is involved and time consuming, not for the faint of heart or unqualified.

#5 Continuing with #4 above, a lot of people do not even know they have a power supply problem in their 4000. I was fortunate (if you want to call it that) enough to have 2 4000 units with this type deal going on. The power supplies provided power, and even gave good voltage readings, however they were not good anymore (age, or whatever). This problem will drive a person nuts because you don't often think to look to the power supply. What happens is the drives will drop in and out as non functional. You put them in, you format them, everything is fine and dandy (or so it seems), then when you reboot the unit (or almost always when you cycle the power), one or more of the drives will drop out and report various errors, usually requiring you to reformat the drive. Like I said, it willd drive you nuts. You will trace problems and read errors and logs and hunt high and low. You will check voltages and all will seem fine but the problem keeps happeneing. Replace the power supply and the problems will disappear. THIS IS A POWER SUPPLY FAILURE. As I also said, many people do not even know their 4000 power supply is failing until it is totaly gone or they assume the problem is the main board. I did some checking around when I discovered this and spoke with some techs who have worked on these 4000's for years (hardware guys) and they confirmed this is very common, not just some fluke that happened to me.

#6 There is a reason the 4000 is slower than the 4100. The 4000 is using a Pentium 233Mhz CPU. With a 100baseT network and using RAID 5, esp with larger arrarys, this is a serious strain on that CPU. RAID 5 requires a lot of XOR calculations for the parity data and this is being done by the CPU. I won't go into it here, and you can go do a lot of reading about this on the net, but I will just tell you, I have seen fast PCs brought to their knees when using a software RAID 3, 5, or 6 doing all the XOR calculations. BTW, the only difference between a software RAID and hardware RAID is that in the software RAID, the system CPU does the work and on a hardware RAID, there is a dedicated CPU on the controller to do the work. In the case of a SNAP, it is kind of a moot point because the system CPU is really only there for this work. You can call it a software RAID if you want, but it is just like a hardware RAID since this is all a SNAP unit does. The exception to this is the occasional JVM you might do if you have JVM installed or the LAN. Ah, now this brings us to the LAN. That network interface will not drag a CPU down all by itself, but it does take a fair amount of CPU when doing streams of data. Add this on top of the XOR calculations that have to be done on the fly as data is changed/written, and well, it is just that much more load on the already strained CPU. I am trying to determine if the SNAP 4000 can handle a CPU upgrade and if so, how much, but I am not very far along on that one yet. I could use some help too (hint hint).

There ya go, there is enough information to chew on for a while about the SNAP 4000 and a lot of it applies to the other SNAPs as well. I hope it helps someone, took me a while to figure all this out and to type all this up for you.




My Theory on #3 above, as promised, is as follows for those who want to know.

As most of you know, the SNAP 4000 uses ATA33. As you also probably know, most all hard drives of today are ATA100 and some are ATA133. In fact a lot of you know the ATA133 drives have had problems with SNAP servers and this ties into my theory. The difference here is that most ATA100 drives detect what the controller is using and switch to that speed, but most ATA133 drives will not do this. They instead will try to force the controller to use their speed or one faster than the controller can do, now enters the problems. I am beginning to suspect this same problem happens with ATA100 drives when they are in C/S mode, or better put, not in M/S mode. I did find some obscure document on Seagate's web site that hinted at this, however because I was not on this track at that point, I glossed over it and since have not been able to find that document again.

There are utilities that you can use to set a drives max ATA speed, but here comes in another problem. With the progress of time, most motherboards/controllers out there anymore support ATA100/133, thus these utilities have not been updated by the drive manufacturers -if- they even still have them. Drive manufacturers being what they are, when they wrote these utilities, wrote in code to look for "qualified" drives to do this to. Meaning they only will work with drives listed in their code and not let you do other drives. Part of this is due to differences between circuit boards being used from different manufacturers, but part of it is just plain those people not wanting you to use their utilities on other manufacturers drives. Well, with the utilities not being updated, most of the newer or larger drives are not built into the code of these utilities. This is what happened in my case so far. I have those 4 Seagate ST3250823A 7200.8 250 GB drives that refuse to work in C/S mode on the SNAP 4000 (they work fine in C/S on a PC) no matter what I have tried. I cannot test my theory out because the Seagate utility that does this does not list this model drive in the utility and won't allow me to change the ATA speed.

[Phoenix32]

Originally Posted by dandrews

Ok I am hard headed but not completely stupid. I let it go through another near 24 hours of repair of the array, again tried to do a backup to the snap and it crashed again. That's it.. This one does not seem to want to run as a raid 5. Therefore back to JBOD... which is fine for home use.

If I can resolve the power supply issue in the other one I have I will try to put a beefier supply in that one, load it up with 230g units and see if that resolves it... afterall, it is all about learning right?

Thanks again for all the post in this wiki... I have learned a great deal in the past few days.

Don

Dave, looks like I am about to have a new best friend huh? lol

[blue68f100]

It's amazing on how problems bring people (total strangers) together.

[dandrews]

Hello Stranger! LOL. Soldering iron is heating up as we speak. Now where are those old ATX supplies and my wire cutters.

[Phoenix32]

Originally Posted by dandrews

Hello Stranger! LOL. Soldering iron is heating up as we speak. Now where are those old ATX supplies and my wire cutters.

And you PM is on the way...

[holzinet]

Hi,

I got a snap server 2200 without drives. Now I have the problem to get an image to the brand new disks I have bought.
I have also another snap, but this is only a 2000. I think, it is not possible to init the disks at the 2000, or is there a trick to do so?

Could somebody please give me a hint, how I can get an image to put it on the disk for the 2200...

[Hallis]

Originally Posted by holzinet

Hi,

I got a snap server 2200 without drives. Now I have the problem to get an image to the brand new disks I have bought.
I have also another snap, but this is only a 2000. I think, it is not possible to init the disks at the 2000, or is there a trick to do so?

Could somebody please give me a hint, how I can get an image to put it on the disk for the 2200...

Putting the hdd's in the 2000 will not prepare them for the 2200 as the OS on the 2000 is largely stored in flash ram. You need the image off of a 2200 or possably an 1100 to makeit work. If you can't find what you're looking for i'll take that 2200 off your hands if the price and shipping are right.

Shane

[holzinet]

Hi Shane,

thanks for the offer, but I would prefer a 'snap2200.bin' image to write it to disk
;-)

I have also a Software-CD with the Snapos.sup, would this help to create an image or whatever?

Without the OS, the Assist-Tool does not help at this situation...

I think, I need an imagefile, right?

Tino

[Hallis]

correct. you need an image file. and a machine or drive with a fat32 file system to have the image file on when you boot to Knoppix to load it to the blank drive.

Shane

[holzinet]

I have two linux machines, so I don't need Knoppix.
But the 2200 image file would be great to have... :-((

Seems to be a bad day for me ...

[blue68f100]

Did you try the 2000 hd in a 2200 to see if it works? I don't think anyone has tried. Remove the drives from the 2000 and install a new master. The main difference it some extra code is loaded for the 2000 that is not used in the 2200. If it boots you will need to reinstall the os.

[holzinet]

Originally Posted by blue68f100

Did you try the 2000 hd in a 2200 to see if it works? I don't think anyone has tried. Remove the drives from the 2000 and install a new master. The main difference it some extra code is loaded for the 2000 that is not used in the 2200. If it boots you will need to reinstall the os.

Yes, I have done exactly this, removed both disks from 2000, installed a 40gb Quantum ATA drive and let it format. After that I've checked via webinterface (Disk status): only 9 Files on the harddisk. After that I've installed this disk into the 2200 - does not work! The power and hd-leds are flashing in sync, both leds blink once in sync, after that the hd led blinks second time, paused, both leds blink once in sync, .... and so on. The link-led is on, the lan-activity flashes sometimes... but gets no ip from dhcp. Waited half an hour, led still flashing in sync the same way. I've also put the 2000 hds into the 2200, same led flashing...
Have also done a "co de format 10000 /reinit" at the 2000 with the mentioned 40gb hd.

I've read in an other thread about a snap2200.rar or snap2200.bin ... But it seems, nobody have this file :-(

It seems, that I have now a new paperweight ...

[blue68f100]

That LED pattern is real common to Snaps when the wrong OS is found. So you will need a 2200 img file to revive it.

[holzinet]

Ok, I've understood ... I'll look for an image file or a working snap 2200 with drives. Two snaps are better than one ;-)

[blue68f100]

If you have a working 2200 you have several option available to you. One is create a image for recovery. The second is let it copy the os over.

[dandrews]

Whooohooo... got the modified PS to power up and spin my drives.

A special thanks to Phoenix32 for all his help and suggestions in how to mod a ATX power supply to use in the 4000. Worked just as he outlined.

I used a ATX supply that is capable of pushing 18 amps on teh +5 and 12 amps on the +12 rails. I decided to add a 2nd fan to the snap just to handle the extra heat generated by this larger supply. Not sure if it would be a problem but I did not want to take a chance. Just used the fan from the mod'ed power supply.

Have a bit of a problem with current draw and spinning up 4 drives at once but I am sure I will find that shortly.

Anyway, 2nd 4000 is now in service. I will let it run for a week or so before I upgrade the drives to 250's. The original 30's are in it now.

Again, thanks for all the help Andy!

Don

[Phoenix32]

Your welcome...

Check all your connectors and your solder joints. That is more than enough power for 4 drives. I am guessing a bad connection if it is still having problems.

[Geek_Ed]

Could his "crashes" be caused by not enough memory? These units are very dependent on memory for RAID operation, so I would assume (yeah, I know the whole ASS-U-ME thing) that more memory would make for a more stable RAID environment.

Just my 2 cents

Ed

[Phoenix32]

Possible, but from his description to me (in a PM), it sounds like he is not getting enough power to the drives, plus the drives currently installed are the original 30 GB drives.