Fragged my friends fuel

SGI hardware problems, solutions, tips, hacks, etc.
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millese
Posts: 5
Joined: Wed Jul 05, 2017 9:38 pm

Fragged my friends fuel

Unread postby millese » Wed Jul 05, 2017 10:37 pm

Hi everyone,
I am a 1st time poster to this site and probably one of the least knowledgeable persons to ever post here. I work in the semi-conductor industry and the scanning electron microscopes we have are run by and SGI fuel with and IP35 700MHZ processor. I have taught myself the tiny bit I know and most of it from this site. For my systems, I run IRIX 6.5 and don't even have enough skills to duplicate a disk on my system so I have been using HDClone professional with a SCSI card in a PC to make disk to disk copies so I have a backup in the event of a failure. My colleague with a similar lack of experience asked me to clone one of his drives for the same type of computer and I managed to destroy his only copy. when the copy completed it said it was unable to verify the copy and there was a checksum error. When he put the drive back in the system we got the following error....

dks0d1s8: volume header not valid
efs read error, bad count
No file system found for "/sash".
Unable to execute dksc(0,1,8)/sash: media not loaded
No volume header on device: dksc(0,1,8)/sash.
Unable to boot; press any key to continue:

Here is what I have found so far, with the 6.5 install package I was able to boot to a sash prompt and thought that I needed to load sash64 from the CD to the volume header but could not seem to get shell to run DVH tool to copy sash64. So at this point to decided to install (for the 1st time in my life) irix to another scsi disk so that I could use DVHTOOL and FX to see what was left of my volume header. When this was all done I did dvhtool for the disk and it came back with some error about not having valid volume header. From there I ran fx 0,2,0 and was able to label->show->partition table and saw that disk only had partition 8 (volume header) in the size of 4096 sectors starting at 0. and partition 10 (volume) staring at 0 and ending 143374805. The partition table on his system is different from mine so made a call to another co-worker who was able to do prtvtoc and saw that the partition table should look like this...
partition Type Fs Start:sec sized:sec
0 xfs yes 8196096 136178709
1 raw 4096 8192000
8 volhdr 0 4096
10 volume 0 1433774805
On a side note after this I was able to use dvhtool, I think this is the case because I read that invoking Fx writes new label, just a guess.
So, assuming that my disk has not been over written all together is there a way to update my SGI labels partition table to add the missing partitions without destroying the data one those partitions? I don't think even having a good disk to DVHtool to copy sash64 over will help because all the disk duplication docs. I have read start with partitioning the disk before doing the copy. Can I use the repartition menu in Fx to make them? Any help would be much appreciated

robespierre
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Joined: Mon Sep 12, 2011 2:28 pm
Location: Boston

Re: Fragged my friends fuel

Unread postby robespierre » Wed Jul 05, 2017 10:58 pm

It appears you have a similar problem to another recent visitor:
viewtopic.php?f=3&t=16731777

My advice in that thread would apply here also.
You have likely blown away the volume header by overwriting it with a PC Master Boot Record (possibly as a result of Windows facilities and not the backup program itself).
You cannot assume the partition layout in this situation, as it has simply been lost and cannot be copied from another disk (which could after all be a different capacity). The only path to recovery is to locate the XFS superblock and recalculate the partition sizes from it.
:PI: :O2: :Indigo2IMP: :Indigo2IMP:

millese
Posts: 5
Joined: Wed Jul 05, 2017 9:38 pm

Re: Fragged my friends fuel

Unread postby millese » Wed Jul 05, 2017 11:06 pm

Thank you very much for the reply! So, these tools are all put together by the same company to run the same hardware. The disk sizes are exactly same with the same size volume. If I were to roll the dice and just duplicate the partition structure and size how would I go about doing that without losing the data already written to the disk?

millese
Posts: 5
Joined: Wed Jul 05, 2017 9:38 pm

Re: Fragged my friends fuel

Unread postby millese » Wed Jul 05, 2017 11:59 pm

Sorry robespierre, I see where you gave me the answer to my question at the end of the post in the link you provided. Thanks again for the help will let you know how it goes.

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Trippynet
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Re: Fragged my friends fuel

Unread postby Trippynet » Thu Jul 06, 2017 1:34 am

I can't really help with the issue you've got, but for future reference, I recommend using xfsdump to clone a drive. There's a full guide on Ian's site which works well.
Systems in use:
:Indigo2IMP: - Nitrogen: R10000 195MHz CPU, 384MB RAM, SolidIMPACT Graphics, 36GB 15k HDD & 300GB 10k HDD, 100Mb/s NIC, New/quiet fans, IRIX 6.5.22
:Fuel: - Lithium: R14000 600MHz CPU, 4GB RAM, V10 Graphics, 72GB 15k HDD & 300GB 10k HDD, 1Gb/s NIC, New/quiet fans, IRIX 6.5.30
Other system in storage: :O2: R5000 200MHz, 224MB RAM, 72GB 15k HDD, PSU fan mod, IRIX 6.5.30

robespierre
Posts: 1555
Joined: Mon Sep 12, 2011 2:28 pm
Location: Boston

Re: Fragged my friends fuel

Unread postby robespierre » Thu Jul 06, 2017 6:16 am

If you want to go that route, which in the circumstances seems to be a rational option, you would do this:
1. insert 6.5 install tools CD
2. stop for maintenance/command prompt

Code: Select all

>> dksc(0,4,8)sash64
sash: dksc(0,4,7)stand/fx.64 -x
fx: (dksc)
fx: ctlr# = (0)
fx: drive# = (1)
fx: lun# = (0)
fx> d
fx/debug> seek 8196096
fx/debug> read 0 1
fx/debug> dump b 0 16

If you see:

Code: Select all

0x0000>  58 46 53 42 ... ... ... ...  XFSB....

Then you know that your disk has an identical layout and the volume is found at the same address.
So if you repopulate the volume header with the copied information, it should work. Make sure your XFS partition really is at the correct address, and there are no overlaps (use a calculator).

Code: Select all

fx/debug> /l/c
fx/label/create> all
fx/label/create> ../set/p
[or use /r/e]

and enter the same partition information you posted above. Save the disklabel:

Code: Select all

fx/label/set> ../sync
fx/label/set> /exit

You also need to copy sash to the volume header, which requires using dvhtool from the miniroot.

Code: Select all

inst: admin
admin: sh
miniroot: # dvhtool -v add /stand/sash64 sash
:PI: :O2: :Indigo2IMP: :Indigo2IMP:

millese
Posts: 5
Joined: Wed Jul 05, 2017 9:38 pm

Re: Fragged my friends fuel

Unread postby millese » Thu Jul 06, 2017 10:20 am

Wow, you just knocked it out of the park! That is exactly what I was looking for, do you think I should read the address before this point and see if it has no reference to XFSB or a reference to a raw partition, or does the XFSB lable only shown at the very start of the partition?

One more thing, when I got to sash using the install disk I have been unable to get to a miniroot. I saw that mr is in 1,6,8 (cdrom for me) directory but typing sh at the sash prompt does not give me a good prompt and I can't use DVHTOOL from that prompt either. I tried to use boot -f dksc(1,6,8)mr but that didn't work. Sorry, again super newb here.
Last edited by foetz on Mon Jul 31, 2017 11:09 am, edited 1 time in total.
Reason: merged

millese
Posts: 5
Joined: Wed Jul 05, 2017 9:38 pm

Re: Fragged my friends fuel

Unread postby millese » Thu Jul 06, 2017 9:13 pm

Ok, so a MASSIVE thank you to robespierre. I was able to follow you instructions and my disk booted. I am really in disbelief. In all of this there is one thing that is baffling me and that is at the end after booting I ran a dvhtool -v l and it only shows sash but sash is the size of the sash file and the 512 of the label. All of my other disks show:
sgilabel 512 2
sash 266240 3

After creating a new label with the new partition table I ran a dvhtool -v and it came up with nothing and when I copied in the sash it shows a single entry
sash 266752 3

Everything works perfectly, just not sure how this happened, but again I am so thankful to you and this site. Also, thanks to trippynet for the advice on future disk cloning.

robespierre
Posts: 1555
Joined: Mon Sep 12, 2011 2:28 pm
Location: Boston

Re: Fragged my friends fuel

Unread postby robespierre » Fri Jul 07, 2017 5:25 am

I'm glad it worked for you!

do you think I should read the address before this point and see if it has no reference to XFSB or a reference to a raw partition, or does the XFSB lable only shown at the very start of the partition?

Disk structures have "magic numbers" for identification, much like the fixed characters at the beginning of some binary files, like '%PDF'. They can be used to ensure that the pointers on disk are not corrupt and prevent some data loss. The first structure in an XFS volume is called the Superblock and its magic number is 'XFSB'. So the very first characters of the volume are 'XFSB': if you see those, you know you are looking at the starting offset of the partition.

One more thing, when I got to sash using the install disk I have been unable to get to a miniroot. I saw that mr is in 1,6,8 (cdrom for me) directory but typing sh at the sash prompt does not give me a good prompt and I can't use DVHTOOL from that prompt either. I tried to use boot -f dksc(1,6,8)mr but that didn't work.

Yes, unfortunately it's more complicated than just running a file. The miniroot file (mr) is an image of a disk volume. It needs to be copied into the swap partition, and then the kernel for your machine (unix.IP35) is loaded by sash with some special flags telling it to use that partition as its root. This is all automatically done for you when you choose "Install System Software" or "Recover System" from the PROM menu. It can also be done by typing commands but they were never properly documented (the -m flag to sash and the "install" sash command are part of it).

The other discrepancy you noted isn't important, as far as I know. The "sgilabel" file isn't required by any software I'm aware of. When you recreated the volume header, it made it empty, and only sash is absolutely necessary to put in it.
:PI: :O2: :Indigo2IMP: :Indigo2IMP:

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opcode
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Re: Fragged my friends fuel

Unread postby opcode » Mon Jul 31, 2017 7:50 am

That was one of the most satisfying threads I have ever read. Robespierre, you just rocked that shit out of the park!
:PrismDT: :Tezro: :Onyx2: :Indigo: :Indigo: :Indigo: :Indigo: :Indigo: :Indigo: :Indy: :Indy: :Indy: :Indy: :Indy: :Indy: :O2: :O2: :O2: :O2: :O2: :1600SW: :1600SW: :320: :Indigo2IMP: :Indigo2: :Octane2: :Octane2: :Octane: :Fuel: :Fuel:
Stolen! :4D310: :Crimson:


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