EVMS 2.5.4 snapshot on Linux 2.6.20

Hi all,

We are  using EVMS 2.5.4 version on Linux kernel version 2.6.16 along. It
was working fine. For some of the other performance reasons, we had to move
to Linux 2.6.20 version - specifically we are currently on 2.6.20-rc6version.

We are observing that the snapshots are not getting created successfully in
this kernel version. Have anyone successfully created a snapshot in this
kernel version yet? We also tried to backtrack the kernel version to
2.6.19.1 but in vain - snapshots are not getting created but the rest of the
EVMS is working fine.

When we create the snapshots, we observe that the snapshot object is getting
successfully created (when we do a query:output) but the corresponding node
is not getting created in (/dev/evms/.nodes) that we want to mount for
accessing the snapshot contents.

We tried to do the following couple of items after going through *somewhat
related issues* reported in the EVMS mail archives but we did not observe
any change in the behavior:

a) Going by (http://marc.theaimsgroup.com/?l=evms-devel&m=112699668724855&w=2)
as suggested by Kevin, we modified the drivers in the kernel source tree
drivers/dm/dm-snap.c and changed the value of SNAPSHOT_PAGES to be that of
64 instead of the currently 256.
b) Going by (http://marc.theaimsgroup.com/?l=evms-devel&m=114536935000036&w=2
), we removed the O_DIRECT flag in plugins/disk/localdskmgr.c while opening
the node.

Both these changes in the 2.5.4 code base refused to make any changes in the
observed behavior. This is what we attempted to do for creating the
snapshots. We have also attached a detailed ('debug' log) for the EVMS
commands that we used.

We would really appreciate if someone can give us a few thoughts on what we
are missing to do as we have been raking our brains on this for quite some
time now....

Sequence of commands that we had given on the EVMS command line:

echo "Create:Region,LVM2={name=Reg__SNAPtestsnapregion,size=1.00GB},
lvm2/raid1/Freespace" | evms -s -d debug

echo "Create:object,Snapshot={original=/dev/evms/siva,snapshot=SNAP__testsnap,Writeable=true},lvm2/raid1/Reg__SNAPtestsnapregion"|
evms -s -d debug

We wanted to attach the relevant debug output files out of running these 2
commands. But for some reason, the mail archiver is not accepting the
zipfile as an attachment currently.

After running the above two commands, the following is the output of query
objects EVMS command (This output is showing the snapshot object created
above):

-bash-3.00# echo q:o | evms

EVMS Command Line Interpreter Version 2.5.4

Engine: The plug-in Linux-HA in module
/usr/local/evms/lib/evms/2.5.4/ha-

1.1.0.so failed to load.  The plug-in's

setup_evms_plugin() function failed with error code 19: No such device.

EVMS:
Logical Disk Name: sda
Major: 8
Minor: 0
Active: TRUE
Logical Disk Size:


465.76 GB
Logical Disk Geometry: 60801 Cylinders, 255 Heads, 63 Sectors per Track,

512 Bytes per Sector
LBA of the 1024 Cylinder Limit: 16434495

Logical Disk Name: sdb
Major: 8
Minor: 16

Active: TRUE


Logical Disk Size: 465.76 GB
Logical Disk Geometry: 60801 Cylinders, 255 Heads, 63 Sectors per Track,

512 Bytes per Sector
LBA of the 1024 Cylinder Limit: 16434495

Logical Disk Name: sdc

Major: 8


Minor: 32
Active: TRUE
Logical Disk Size: 496.00 MB
Logical Disk Geometry: 63 Cylinders, 16 Heads, 62 Sectors per Track, 512

Bytes per Sector
LBA of the 1024 Cylinder Limit: 1015808


Segment Name: sda_mbr


Major: 0
Minor: 0
Active: FALSE
Segment Size: 31.50 KB
Starting LBA: 0
Segment Type: Metadata

Segment Name: sda1

Major: 253
Minor: 1
Active: TRUE

Segment Size: 465.76 GB
Starting LBA: 63


Segment Type: Data

Segment Name: sda_freespace1
Major: 0
Minor: 0
Active: FALSE
Segment Size: 2.49 MB
Starting LBA: 976768065

Segment Type: Freespace


Segment Name: sdb_mbr
Major: 0


Minor: 0
Active: FALSE
Segment Size: 31.50 KB
Starting LBA: 0
Segment Type: Metadata

Segment Name: sdb1
Major: 253
Minor: 0

Active: TRUE

Segment Size: 465.76 GB
Starting LBA: 63

Segment Type: Data

Segment Name: sdb_freespace1
Major: 0
Minor: 0
Active: FALSE
Segment Size: 2.49 MB
Starting LBA: 976768065
Segment Type: Freespace




Segment Name: sdc_mbr
Major: 0
Minor: 0
Active: FALSE
Segment Size: 31.00 KB
Starting LBA: 0
Segment Type: Metadata

Segment Name: sdc1
Major: 0
Minor: 0
Active: FALSE
Segment Size: 495.97 MB
Starting LBA: 62
Segment Type: Data

Region Name: lvm2/raid1/Reg__SNAPtestsnapregion
Major: 253
Minor: 8
Active: TRUE
Region Size: 1.00 GB
Region Type: Data

Region Name: lvm2/raid1/Regshare1
Major: 253
Minor: 2
Active: TRUE
Region Size: 20.00 GB
Region Type: Data

Region Name: lvm2/raid1/Regshare2
Major: 253
Minor: 4
Active: TRUE
Region Size: 20.00 GB
Region Type: Data

Region Name: lvm2/raid1/Regsiva
Major: 253
Minor: 9
Active: TRUE
Region Size: 1.00 GB
Region Type: Data

Region Name: lvm2/raid1/Freespace
Major: 0
Minor: 0
Active: FALSE
Region Size: 423.75 GB
Region Type: Freespace

Region Name: md/md0
Major: 9
Minor: 0
Active: TRUE
Region Size: 465.76 GB
Region Type: Data

Object Name: SNAP__testsnap
Major: 0
Minor: 0
Active: FALSE
Object Size: 1024.00 MB

Object Name: lvm2/raid1/Regsiva#origin#
Major: 253
Minor: 6
Active: TRUE
Object Size: 1.00
 GB

After analyzing the above log file, we saw that the activate snap was
returning with an error message but not sure of whether the failure is
because of this error message and if so, what should we do to correct this?
The below is the referred extract from this log file that we are referring:

/********************** POSSIBLE ERROR MESSAGE ***************************/
Feb 06 18:54:25 sanat _7_ Snapshot: activate_snapshot: Exit.  Return value
= 22
Feb 06 18:54:25 sanat _7_ Snapshot: snap_activate: Exit.  Return value = 22
Feb 06 18:54:25 sanat _8_ Engine: activate_object:
activate(SNAP__testsnap) returned 22: Invalid argument
Feb 06 18:54:25 sanat _7_ Engine: activate_object: Exit.  Return value is 22.
Feb 06 18:54:25 sanat _3_ Engine: activate: Error code 22 activating
object SNAP__testsnap: Invalid argument
/***********************POSSIBLE ERROR MESSGAE***************************/


Please help.

Thanks,

Srini

-------------------------------------------------------------------------
Using Tomcat but need to do more? Need to support web services, security?
Get stuff done quickly with pre-integrated technology to make your job easier.
Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642

_______________________________________________
Evms-devel mailing list
[email protected]
To subscribe/unsubscribe, please visit:
https://lists.sourceforge.net/lists/listinfo/evms-devel