[9fans] Plan9 installation invading the other partitions?

[9fans] Plan9 installation invading the other partitions?

[Lluís Batlle i Rossell]

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I just installed plan9 in my PC, where there are many partitions. I can
give you a "fdisk -l /dev/hda":
omitting empty partition (8)

Disk /dev/hda: 40.0 GB, 40020664320 bytes
16 heads, 63 sectors/track, 77545 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

    Device Boot      Start         End      Blocks   Id  System
/dev/hda1               1         128       64480+  83  Linux
/dev/hda2   *         129       20318    10175760   39  Plan 9
/dev/hda3           20319       20839      262584   82  Linux swap / Solaris
/dev/hda4           20840       77543    28578767+   f  W95 Ext'd (LBA)
/dev/hda5           20840       41157    10240240+  83  Linux
/dev/hda6           41158       52784     5859976+  83  Linux
/dev/hda7           52785       77542    12478000+  83  Linux


I did the Plan9 partition using Linux fdisk. Well... after the plan9 CD
installation (I downloaded the iso a few hours ago), I started linux
again and the SuperBlock of my Reiserfs partition /dev/hda7 had been
overwritten. I had to run reiserfsck --rebuild-sb, and it fixed almost
everything. Further reiser checking fixed something with two tmp files
(the partition is quite full and with many files. Nice only two files
were bad.)

I don't know if I'm the only one having problems with PC partitions (I
guess not), but I'd prefer feeling like Plan9 couldn't have done this
little exter-partition writting.

I hope running Plan9 won't break anything more. hda7 is my linux /home
partition.

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Re: [9fans] Plan9 installation invading the other partitions?

[Russ Cox]

Apparently someone removed the part in the
installation instructions where it says you should
backup your hard disk before installing Plan 9.

That said, I don't believe that Plan 9 actually wrote
to your hda7.  That's a very long way away from the
Plan 9 partition.  I think it's more likely that your disk
is going bad.

In Plan 9, cat /dev/sdC0/ctl and see whether the block
numbers given for the offsets of the various partitions
make sense compared against your Linux fdisk output.

Russ

Re: [9fans] Plan9 installation invading the other partitions?

[Lluís Batlle]

While trying to get certain Plan9 isn't guilty, I looked at the SMART
data of the HD. I'm not an expert on that, but the error log says:
=== START OF READ SMART DATA SECTION ===
SMART Error Log Version: 1
No Errors Logged

The information of my HD is:
SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE
UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   072   068   034    Pre-fail
Always       -       189802098
  3 Spin_Up_Time            0x0003   070   070   000    Pre-fail
Always       -       0
  4 Start_Stop_Count        0x0032   099   099   020    Old_age
Always       -       1389
  5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail
Always       -       0
  7 Seek_Error_Rate         0x000f   081   060   030    Pre-fail
Always       -       154801045
  9 Power_On_Hours          0x0032   087   087   000    Old_age
Always       -       11801
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail
Always       -       0
 12 Power_Cycle_Count       0x0032   099   099   020    Old_age
Always       -       1677
194 Temperature_Celsius     0x0022   047   051   000    Old_age
Always       -       47
195 Hardware_ECC_Recovered  0x001a   072   068   000    Old_age
Always       -       189802098
197 Current_Pending_Sector  0x0012   100   100   000    Old_age
Always       -       0
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age
Offline      -       0
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age
Always       -       0
200 Multi_Zone_Error_Rate   0x0000   100   253   000    Old_age
Offline      -       0
202 TA_Increase_Count       0x0032   100   253   000    Old_age
Always       -       0

I hope you understand those values better than I do, and can take a conclusion.

I never had a SuperBlock overwritten, and I deal with PC partitions
since some years ago. I've only seen that after installing Plan9. I
even didn't modify my grub before finding the SB error.

I forgot looking at the partition information in Plan9 - now I can't,
I will soon say something about that in this same thread.

Thanks,
Lluís.

2006/7/20, Russ Cox <rsc@swtch.com>:
> Apparently someone removed the part in the
> installation instructions where it says you should
> backup your hard disk before installing Plan 9.
>
> That said, I don't believe that Plan 9 actually wrote
> to your hda7.  That's a very long way away from the
> Plan 9 partition.  I think it's more likely that your disk
> is going bad.
>
> In Plan 9, cat /dev/sdC0/ctl and see whether the block
> numbers given for the offsets of the various partitions
> make sense compared against your Linux fdisk output.
>
> Russ
>

Re: [9fans] Plan9 installation invading the other partitions?

[Christian Walther]

Hi,

I wouldn't blame Plan 9 for damaging another partition it shouldn't
even touch. I'd blame ReiserFS. I heard several stories from friends
and collegues who used ReiserFS about file system corruption. You
might want to use your favorite search engine, but from my point of
view ReiserFS isn't stable enough for everydays use.
The alternatives are either called ext3 or jfs, I suppose. XFS is
nice, too, but it tends to corrupt the file system in case of a sudden
system crash (e.g. after power fail), especially on heavy loaded file
systems.

Christian

Re: [9fans] Plan9 installation invading the other partitions?

[Lluís Batlle]

2006/7/21, Christian Walther <cptsalek@gmail.com>:
> Hi,
>
> I wouldn't blame Plan 9 for damaging another partition it shouldn't
> even touch. I'd blame ReiserFS. I heard several stories from friends
> and collegues who used ReiserFS about file system corruption. You
> might want to use your favorite search engine, but from my point of
> view ReiserFS isn't stable enough for everydays use.
> The alternatives are either called ext3 or jfs, I suppose. XFS is
> nice, too, but it tends to corrupt the file system in case of a sudden
> system crash (e.g. after power fail), especially on heavy loaded file
> systems.
Yes, I heard that also about ReiserFS. But practically, I've lost
files using ext3 (I used it for some months). Too many, so I stopped
using it. I've never lost files using ReiserFS (since years of usage)
until this week - and only two tmp files were lost. About XFS, which I
used for a year or so, had namely the problem of sudden system crash.
The filesystem didn't get corrupted, but simply some files (mostly
important ones) were blank after reboot.

About blaming Plan9... I only wanted to help catching an important
problem, if the problem is there. This way I planned giving as much
information as possible. Sorry if my words sound like a blame - my
English is poor, and I often miss those writting nuances.

Regards,

Re: [9fans] Plan9 installation invading the other partitions?

[Iruatã Souza (muzgo)]

2006/7/21, Lluís Batlle <viriketo@gmail.com>:
> Yes, I heard that also about ReiserFS. But practically, I've lost
> files using ext3 (I used it for some months). Too many, so I stopped
> using it. I've never lost files using ReiserFS (since years of usage)
> until this week - and only two tmp files were lost. About XFS, which I
> used for a year or so, had namely the problem of sudden system crash.
> The filesystem didn't get corrupted, but simply some files (mostly
> important ones) were blank after reboot.
>
> About blaming Plan9... I only wanted to help catching an important
> problem, if the problem is there. This way I planned giving as much
> information as possible. Sorry if my words sound like a blame - my
> English is poor, and I often miss those writting nuances.

I had a problem kinda like yours but there was half the disk for
OpenBSD and the other  half was planned to run Plan 9. I remember
Plan9 installation corrupted the PBR and my BSD disklabel.
After I created the Plan9 space with OpenBSD's fdisk, Plan9 installed just fine.

Regards,

Iruatã Souza (muzgo)

Re: [9fans] Plan9 installation invading the other partitions?

[Harri Haataja]

On Fri, Jul 21, 2006 at 01:51:44PM +0200, Lluís Batlle wrote:
> 2006/7/21, Christian Walther <cptsalek@gmail.com>:
> >I wouldn't blame Plan 9 for damaging another partition it shouldn't
> >even touch. I'd blame ReiserFS. I heard several stories from friends
> >and collegues who used ReiserFS about file system corruption. You
> >might want to use your favorite search engine, but from my point of
> >view ReiserFS isn't stable enough for everydays use.
> >The alternatives are either called ext3 or jfs, I suppose. XFS is
> >nice, too, but it tends to corrupt the file system in case of a
> >sudden system crash (e.g. after power fail), especially on heavy
> >loaded file systems.
> Yes, I heard that also about ReiserFS. But practically, I've lost
> files using ext3 (I used it for some months). Too many, so I stopped
> using it. I've never lost files using ReiserFS (since years of usage)
> until this week - and only two tmp files were lost. About XFS, which I
> used for a year or so, had namely the problem of sudden system crash.
> The filesystem didn't get corrupted, but simply some files (mostly
> important ones) were blank after reboot.

I've taken damage on reiserfs and found out that there wasn't really
much anything in a way of recovery tools or diagnostics. About
everything anything managed to say that the fs is dead. XFS is still the
only system that I've had nearly guaranteed data loss (and not much sign
of when or where until you find the blank files) if anything goes wrong
with a fs in use. Never on Irix, though. There it always worked
flawlessly despite equal randomness in power status and hardware faults
etc.
At the moment (well, that means the last few years; installations aren't
that frequent) I'm sticking to ext3 on any Linux hosts I may be looking
after.

-- 
"What do you mean? A handgun is a standard tool for a sysadmin, isn't it?"
		-- Kurt M. Hockenbury, Scary Devil Monastery

Re: [9fans] Plan9 installation invading the other partitions?

[erik quanstrom]

i never had any trouble with jfs/lvm on aix.  i'd recommend that combination
on linux, too.  i actually use reiserfs/lvm on linux.  i think the chief advantage is being
able to avoid all but basic partitioning.  fdisk is not your friend. do not trust
it with your data. ☺

- erik

On Sun Jul 23 19:23:20 CDT 2006, harriha@mail.student.oulu.fi wrote:
> At the moment (well, that means the last few years; installations aren't
> that frequent) I'm sticking to ext3 on any Linux hosts I may be looking
> after.

Re: [9fans] Plan9 installation invading the other partitions?

[Paweł Lasek]

On 7/24/06, Harri Haataja <harriha@mail.student.oulu.fi> wrote:
> I've taken damage on reiserfs and found out that there wasn't really
> much anything in a way of recovery tools or diagnostics. About
> everything anything managed to say that the fs is dead. XFS is still the
> only system that I've had nearly guaranteed data loss (and not much sign
> of when or where until you find the blank files) if anything goes wrong
> with a fs in use. Never on Irix, though. There it always worked
> flawlessly despite equal randomness in power status and hardware faults
> etc.
> At the moment (well, that means the last few years; installations aren't
> that frequent) I'm sticking to ext3 on any Linux hosts I may be looking
> after.

I only wonder since I've _never_ had data loss with XFS while I
managed to destroy around 40% of data by shutting down power to
ReiserFS :-)


--
Paul Lasek