IDS Forum

RE: is there a way to find out the physical de....

Posted By: jim-cramer@uiowa.edu
Date: Thursday, 16 June 2011, at 5:17 p.m.

In Response To: Re: is there a way to find out the physical device (Art Kagel)

Hi Art,

Well, no doubt about it, you are THE MAN! I *almost* have the server
back up (see below). Good news and bad news.

Thanks very much for the clever way of recreating lost symbolic links
used originally to create chunks and pointing these links at the actual
chunk device file paths/names. This method is based upon your expert
knowledge
of chunk storage internals.

I used your method to get the chunk number for each chunk/block device
file (using RAW chunks), looked for that number in the oncfg file's
"Chunks" section, got the name of the symbolic link used to create
the chunk from that line in the file, and created a script to recreate
the symbolic links/pathnames that had been used in the onspaces commands
that created the chunks.

The server begins to start with the "oninit" command, but it ABORTS.
According to the online.log file, it gets quite a ways through startup
but finds something wrong, Errno 2 (missing file or directory?)
with chunk 1, my rootdbs. I have included the tail end of the log file,
starting just before the warning about chunk 1, continuing to the end.

Any ideas? It seems like perhaps I made a mistake with the creation of
the symbolic link for rootdbs, but it looks OK I think. The "ls -l" of it
produces:

lrwxrwxrwx 1 root root 19 Jun 16 15:18 /dev/rootdbs ->
/dev/VolGrp01/vol01

and the rootdbs link points to another link, and ls -l on that link
produces:

lrwxrwxrwx 1 root root 26 Jun 15 15:49 /dev/VolGrp01/vol01 ->
/dev/mapper/VolGrp01-vol01

and ls -l on the target of that link, the block device file for the LV that
I used to create Chunk 1 with, produces:

brw-rw---- 1 informix informix 253, 5 Jun 15 10:49
/dev/mapper/VolGrp01-vol01

The "ls -lL /dev/rootdbs" command produces:

brw-rw---- 1 informix informix 253, 5 Jun 15 10:49 /dev/rootdbs

I am new to Linux (SUSE 11 SLES) and trying to migrate IDS from HPUX to it.
I
do not really understand the "device-mapper" Linux functionality that is
creating
symbolic links instead of Logical Volume device files in the traditional
directory
created for the Volume Group that the LVs belong to, and pointing those
links in
the VG dir to /dev/mapper, where the device files for the LV actually
reside.

So, due to my lack of knowledge of mapper, the following might be the
problem and
I would appreciate your opinion on it.

Originally I created the sym links in /dev to point straight at the device
file
in /dev/mapper. For example, the rootdbs was created with:

ln -s /dev/mapper/VolGrp01-vol01b /dev/rootdbs

However, due to some discussions with our Linux Sys Admins here, I have
recreated
the links in /dev to point to the sym links in the /dev/vgxx dir, which then
point
to the actual device files that I have set the ownershiip and permissions on

correctly.

The rootdbs was created with the path /dev/rootdbs, and the "ls -lL" on that
sym link/path
shows the target of this double-linking to be:

brw-rw---- 1 informix informix 253, 5 Jun 15 10:49 /dev/rootdbs

which looks OK permissions and ownership-wise, but perhaps the double
linking is the problem?

What do you think? Sorry this is so long. Thanks for bearing with me.

Jim

15:30:20 Event notification facility epoll enabled.
15:30:20 IBM Informix Dynamic Server Version 11.70.FC1GE Software Serial
Number AAA#B000000
15:30:20 Warning: stat() failed for chunk file /dev/rootdbs
15:30:22 IBM Informix Dynamic Server Initialized -- Shared Memory
Initialized.

15:30:22 Started 1 B-tree scanners.
15:30:22 B-tree scanner threshold set at 5000.
15:30:22 B-tree scanner range scan size set to -1.
15:30:22 B-tree scanner ALICE mode set to 6.
15:30:22 B-tree scanner index compression level set to med.
15:30:22 Physical Recovery Started at Page (2:131643).
15:30:23 Physical Recovery Complete: 8 Pages Examined, 8 Pages Restored.
15:30:23 Logical Recovery Started.
15:30:23 Dynamically allocated new virtual shared memory segment (size
8192KB)
15:30:23 Memory sizes:resident:192512 KB, virtual:253840 KB,
SHMTOTAL:16777216 KB
15:30:23 10 recovery worker threads will be started.
15:30:23 Assert Warning: I/O read chunk 1, pagenum 6641, pagecnt 1 -->
errno = 2
15:30:23 IBM Informix Dynamic Server Version 11.70.FC1GE
15:30:23 Who: Session(9, informix@s-l008, 0, 0x50291c20)

Thread(29, xchg_1.2, 502519a8, 3)

File: rsbuff.c Line: 6302
15:30:23 Action: Please notify IBM Informix Technical Support.
15:30:23 stack trace for pid 12822 written to /opt/db/ids/tmp/af.40567de
15:30:23 See Also: /opt/db/ids/tmp/af.40567de
15:30:23 I/O read chunk 1, pagenum 6641, pagecnt 1 --> errno = 2
15:30:23 Rollforward of log record failed. iserrno = 126
15:30:23 Log Record: log = 27, pos = 0x3ef8518, type = OLDRSAM:HINSERT(40),
trans = 26
15:30:23 Assert Failed: INFORMIX-OnLine Must ABORT

Critical media failure.
15:30:23 IBM Informix Dynamic Server Version 11.70.FC1GE
15:30:23 Who: Session(9, informix@s-l008, 0, 0x50291c20)

Thread(29, xchg_1.2, 502519a8, 3)

File: rsmirror.c Line: 1734
15:30:23 stack trace for pid 12822 written to /opt/db/ids/tmp/af.40567de
15:30:23 See Also: /opt/db/ids/tmp/af.40567de, shmem.40567de.0
15:30:28 Starting crash time check of:
15:30:28 1. memory block headers
15:30:28 2. stacks
15:30:28 Crash time checking found no problems
15:30:28 rsmirror.c, line 1734, thread 29, proc id 12822, INFORMIX-OnLine
Must ABORT

Critical media failure..
15:30:29 Fatal error in ADM VP at mt.c:14250
15:30:29 Unexpected virtual processor termination, pid = 12822, exit =
0x100

15:30:29 PANIC: Attempting to bring system down

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of Art
Kagel
Sent: Thursday, June 16, 2011 1:34 PM
To: ids@iiug.org
Subject: Re: is there a way to find out the physical de.... [24060]

Unfortunately, no. Informix only stored the links you provide, it does not
follow the links to their core names at all, it depends on the OS to
maintain and promote the links.

HOWEVER, there is one way. Use dd piped to od -x to read the first few
pages (so 2K each if you used the default pagesize or whatever the pagesize
of the dbspaces were) of each chunk's physical device. The first six bytes
of each page have the chunk number encoded. So on my server for chunk #1:

$ dd if=/opt/informix/infmx.11.70.FC1B7/dbspaces/rootdb.1.chunk bs=2k
count=2|od -x
2+0 records in
2+0 records out
4096 bytes (4.1 kB) copied, 0.00441886 s, 927 kB/s
0000000 *0000 0000 0001* 9600 0003 1800 0130 06c0
0000020 0000 0000 0000 0000 4249 204d 6e49 6f66

For chunk #6:

$ dd if=/opt/informix/infmx.11.70.FC1B7/dbspaces/tempdbs1.1.chunk bs=2k
count=1|od -x
1+0 records in
1+0 records out
2048 bytes (2.0 kB) copied, 7.7661e-05 s, 26.4 MB/s
0000000 *0000 0000 0006* 492e 0000 1800 0018 07e4
0000020 0000 0000 0000 0000 0000 0000 0000 0000

Armed with the chunk numbers you should be able to recreate the links.

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
Blog: http://informix-myview.blogspot.com/

Disclaimer: Please keep in mind that my own opinions are my own opinions and

do not reflect on my employer, Advanced DataTools, the IIUG, nor any other
organization with which I am associated either explicitly, implicitly, or by

inference. Neither do those opinions reflect those of other individuals
affiliated with any entity with which I am affiliated nor those of the
entities themselves.

On Thu, Jun 16, 2011 at 2:23 PM, jim-cramer@uiowa.edu
<jim-cramer@uiowa.edu>wrote:

> Help!
>
> 11.70.FC1 on Linux SUSE 11 SLES
>
> After setting up a 11.7 IDS instance and creating a bunch
> of Logical Volumes, creating Symbolic Links in /dev that
> pointed to the block device files that the LV Manager created,
> changing the ownership and permission on these device files
> appropriately, creating dbspaces from the chunks *using the
> Symbolic Link pathnames* to the chunk device files,
> I found out that when the Linux system was rebooted all
> of the Symbolic Links for my Informix Chunks were deleted
> from /dev (and also that the ownership and permissions for the
> chunk devices files had reverted to my pre-configured state).
>
> I need to re-create the symbolic links for the chunks, in
> some non-system directory I assume.
>
> The names of the symbolic links that I created indicated
> what dbspace the each chunk belonged to. I have those link names in
> my $INFORMIXDIR/etc/oncfg_servername.0 file as the pathname
> to each Chunks.
>
> UNFORTUNATELY, the names that I gave the Logical
> Volumes, and hence the names of the devices files created
> for the LVs/Chunks, did not indicate which Chunk/DBSpace
> each was created for (i.e.: I used a systematic pattern vol01,
> vol02, vol02,...)
>
> So, I need a way to find out the physical device file pathname
> that each of the symbolic links had pointed to, so that I
> can recreate the links correctly.
>
> OR
>
> since those links have been blown away by the OS and the instance
> is down, is there a file somewhere where I would find this info?
>
> Or
>
> is there an Informix Utility that can be run against a down instance
> that would list out the chunks that had been created for that instance
> along with the physical device file pathname for each?
>
> Any information or ideas would be appreciated.
>
> Thanks,
>
> Jim Cramer
> Univ of Iowa
>
>
>
>
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>
>

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Messages In This Thread

• is there a way to find out the physical device fil
  jim-cramer@uiowa.edu -- Thursday, 16 June 2011, at 2:23 p.m.
  • Re: is there a way to find out the physical device
    Art Kagel -- Thursday, 16 June 2011, at 2:34 p.m.
    • RE: is there a way to find out the physical de....
      jim-cramer@uiowa.edu -- Thursday, 16 June 2011, at 5:17 p.m.
      • Re: is there a way to find out the physical de....
        Art Kagel -- Thursday, 16 June 2011, at 6:59 p.m.
        • Re: is there a way to find out the physical de....
          jim-cramer@uiowa.edu -- Friday, 17 June 2011, at 9:41 a.m.
          • Re: is there a way to find out the physical de....
            Art Kagel -- Friday, 17 June 2011, at 10:09 a.m.
            • RE: is there a way to find out the physical de....
              jim-cramer@uiowa.edu -- Friday, 17 June 2011, at 10:57 a.m.
              • RE: is there a way to find out the physical de....
                Jamie Gedye -- Friday, 17 June 2011, at 1:16 p.m.
                • RE: is there a way to find out the physical de....
                  Cramer, James A -- Monday, 20 June 2011, at 1:43 p.m.
                  • RE: is there a way to find out the physical de....
                    Jamie Gedye -- Monday, 20 June 2011, at 3:07 p.m.
                    • RE: is there a way to find out the physical de....
                      Cramer, James A -- Monday, 20 June 2011, at 5:39 p.m.
        • RE: is there a way to find out the physical de....
          jim-cramer@uiowa.edu -- Monday, 20 June 2011, at 1:31 p.m.
          • Re: is there a way to find out the physical de....
            Art Kagel -- Monday, 20 June 2011, at 2:23 p.m.
            • RE: is there a way to find out the physical de....
              Cramer, James A -- Monday, 20 June 2011, at 2:48 p.m.
        • RE: is there a way to find out the physical de....
          jim-cramer@uiowa.edu -- Tuesday, 21 June 2011, at 1:06 p.m.
          • Re: is there a way to find out the physical de....
            Art Kagel -- Tuesday, 21 June 2011, at 1:14 p.m.
            • RE: is there a way to find out the physical de....
              Wyza, Jonathon -- Tuesday, 21 June 2011, at 1:56 p.m.
              • RE: is there a way to find out the physical de....
                jim-cramer@uiowa.edu -- Tuesday, 21 June 2011, at 2:44 p.m.
            • RE: is there a way to find out the physical de....
              jim-cramer@uiowa.edu -- Tuesday, 21 June 2011, at 2:30 p.m.
            • Re: is there a way to find out the physical de....
              rroussey@comcast.net -- Tuesday, 21 June 2011, at 6:05 p.m.
              • RE: is there a way to find out the physical de....
                jim-cramer@uiowa.edu -- Tuesday, 21 June 2011, at 7:01 p.m.

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