Steven,

As I said yesterday, I made a mistake with my version which is 5.0 GA.

According to http://seer.entsupport.symantec.com/docs/316981.htm, dmp_fast_recovery should be applicable to 5.0 on Solaris :

Products Applied:
Volume Manager for UNIX/Linux 4.1 MP2 (Solaris), 4.1 MP2 (Solaris) RP5, 5.0 (Solaris), 5.0 MP1 (Solaris), 5.0 MP3 (Solaris), 5.0 MP3 (Solaris) RP1, 5.0 MP3 (Solaris) RP2, 5.0 MP3 (Solaris) RP3



Le 16/09/2010 20:31, Green, Steven a écrit :
Check the technote again ... It specifically lists only AIX as the applicable OS. Also, your modinfo output suggests you are not running MP3 anyway. Here is my modinfo output from a Solaris 10 system running VxVM 5.0 MP3:

[kultarr:root]: modinfo | grep -i vx
 40 7be08000  3e4e0 183   1  vxdmp (VxVM 5.0MP3: DMP Driver)
 42 7ba00000 209248 184   1  vxio (VxVM 5.0MP3 I/O driver)
 44 7be073c0    c78 265   1  vxspec (VxVM 5.0MP3 control/status driv)
201 7be75228    cb0 266   1  vxportal (VxFS 5.0_REV-5.0MP3A25_sol port)
202 7aa00000 1d89e0  21   1  vxfs (VxFS 5.0_REV-5.0MP3A25_sol SunO)
224 7abe4000   a9e0 267   1  fdd (VxQIO 5.0_REV-5.0MP3A25_sol Qui)


-----Original Message-----
From: Sebastien DAUBIGNE [mailto:sebastien.daubi...@atosorigin.com] 
Sent: Thursday, September 16, 2010 8:41 AM
To: Veritas-vx@mailman.eng.auburn.edu
Subject: Re: [Veritas-vx] Solaris-SFS / MPxIO / VxVM failover issue

  Thank you Victor and William, it seems to be a very good lead.

Unfortunately, this tunable seems not to be supported in the VxVM 
version installed on my system :

 > vxdmpadm gettune dmp_fast_recovery
VxVM vxdmpadm ERROR V-5-1-12015  Incorrect tunable
vxdmpadm gettune [tunable name]
Note - Tunable name can be dmp_failed_io_threshold, dmp_retry_count, 
dmp_pathswitch_blks_shift, dmp_queue_depth, dmp_cache_open, 
dmp_daemon_count, dmp_scsi_timeout, dmp_delayq_interval, dmp_path_age, 
or dmp_stat_interval

Something odd because my version is 5.0 MP3 Solaris SPARC, and according 
to http://seer.entsupport.symantec.com/docs/316981.htm this tunable 
should be available.

 > modinfo | grep -i vx
  38 7846a000  3800e 288   1  vxdmp (VxVM 5.0-2006-05-11a: DMP Drive)
  40 784a4000 334c40 289   1  vxio (VxVM 5.0-2006-05-11a I/O driver)
  42 783ec71d    df8 290   1  vxspec (VxVM 5.0-2006-05-11a control/st)
296 78cfb0a2    c6b 291   1  vxportal (VxFS 5.0_REV-5.0A55_sol portal )
297 78d6c000 1b9d4f   8   1  vxfs (VxFS 5.0_REV-5.0A55_sol SunOS 5)
298 78f18000   a270 292   1  fdd (VxQIO 5.0_REV-5.0A55_sol Quick )





Le 16/09/2010 12:15, Victor Engle a écrit :
Which version of veritas? Version 4/2MP2 and version 5.x introduced a
feature called DMP fast recovery. It was probably supposed to be
called DMP fast fail but "recovery" sounds better. It is supposed to
fail suspect paths more aggressively to speed up failover. But when
you only have one vxvm DMP path, as is the case with MPxIO, and
fast-recovery fails that path, then you're in trouble. In version 5.x,
it is possible to disable this feature.

Google DMP fast recovery.

http://seer.entsupport.symantec.com/docs/307959.htm

I can imagine there must have been some internal fights at symantec
between product management and QA to get that feature released.

Vic





On Thu, Sep 16, 2010 at 6:03 AM, Sebastien DAUBIGNE
<sebastien.daubi...@atosorigin.com>  wrote:
  Dear Vx-addicts,

We encountered a failover issue on this configuration :

- Solaris 9 HW 9/05
- SUN SAN (SFS) 4.4.15
- Emulex with SUN generic driver (emlx)
- VxVM 5.0-2006-05-11a

- storage on HP SAN (XP 24K).


Multipathing is managed by MPxIO (not VxDMP) because the SAN team and HP
support imposed the Solaris native solution for multipathing :

VxVM ==>  VxDMP ==>  MPxIO ==>  FCP ...

We have 2 paths to the switch, linked to 2 paths to the storage, so the
LUNs have 4 paths, with active/active support.
Failover operation has been tested successfully by offlining each port
successively on the SAN.

We regulary have transient I/O errors (scsi timeout, I/O error retries
with "Unit attention"), due to SAN-side issues. Usually these errors are
transparently managed by MPxIO/VxVM without impact on the applications.

Now for the incident we encountered :

One of the SAN port was reset , consequently there were some transient
I/O error.
The other SAN port was OK, so the MPxIO multipathing layer should have
failover the I/O on the other path, without transmiting the error to the
VxDMP layer.
For some reason, it did not failover the I/O before VxVM caught it as
unrecoverable I/O error, disabling the subdisk and consequently the
filesystem.

Note the "giving up" message from scsi layer at 06:23:03 :

Sep  1 06:18:54 myserver vxdmp: [ID 917986 kern.notice] NOTICE: VxVM
vxdmp V-5-0-112 disabled path 118/0x558 belonging to the dmpnode 288/0x60
Sep  1 06:18:54 myserver vxdmp: [ID 824220 kern.notice] NOTICE: VxVM
vxdmp V-5-0-111 disabled dmpnode 288/0x60
Sep  1 06:18:54 myserver vxdmp: [ID 917986 kern.notice] NOTICE: VxVM
vxdmp V-5-0-112 disabled path 118/0x538 belonging to the dmpnode 288/0x20
Sep  1 06:18:54 myserver vxdmp: [ID 917986 kern.notice] NOTICE: VxVM
vxdmp V-5-0-112 disabled path 118/0x550 belonging to the dmpnode 288/0x18
Sep  1 06:18:54 myserver vxdmp: [ID 824220 kern.notice] NOTICE: VxVM
vxdmp V-5-0-111 disabled dmpnode 288/0x20
Sep  1 06:18:54 myserver vxdmp: [ID 824220 kern.notice] NOTICE: VxVM
vxdmp V-5-0-111 disabled dmpnode 288/0x18
Sep  1 06:18:54 myserver scsi: [ID 107833 kern.warning] WARNING:
/scsi_vhci/s...@g60060e80152777000001277700003794 (ssd165):
Sep  1 06:18:54 myserver        SCSI transport failed: reason
'tran_err': retrying command
Sep  1 06:19:05 myserver scsi: [ID 107833 kern.warning] WARNING:
/scsi_vhci/s...@g60060e80152777000001277700003794 (ssd165):
Sep  1 06:19:05 myserver        SCSI transport failed: reason 'timeout':
retrying command
Sep  1 06:21:57 myserver scsi: [ID 107833 kern.warning] WARNING:
/scsi_vhci/s...@g60060e8015277700000127770000376d (ssd168):
Sep  1 06:21:57 myserver        SCSI transport failed: reason
'tran_err': retrying command
Sep  1 06:22:45 myserver scsi: [ID 107833 kern.warning] WARNING:
/scsi_vhci/s...@g60060e8015277700000127770000376d (ssd168):
Sep  1 06:22:45 myserver        SCSI transport failed: reason 'timeout':
retrying command
Sep  1 06:23:03 myserver scsi: [ID 107833 kern.warning] WARNING:
/scsi_vhci/s...@g60060e80152777000001277700003787 (ssd166):
Sep  1 06:23:03 myserver        SCSI transport failed: reason 'timeout':
giving up
Sep  1 06:23:03 myserver vxio: [ID 539309 kern.warning] WARNING: VxVM
vxio V-5-3-0 voldmp_errbuf_sio_start: Failed to flush the error buffer
300ce41c340 on device 0x1200000003a to DMP
Sep  1 06:23:03 myserver vxio: [ID 771159 kern.warning] WARNING: VxVM
vxio V-5-0-2 Subdisk mydisk_2-02 block 5935: Uncorrectable write error
Sep  1 06:23:03 myserver vxfs: [ID 702911 kern.warning] WARNING: msgcnt
1 mesg 037: V-2-37: vx_metaioerr - vx_logbuf_clean -
/dev/vx/dsk/mydg/vol1 file system meta data write error in dev/block 0/5935
Sep  1 06:23:03 myserver vxfs: [ID 702911 kern.warning] WARNING: msgcnt
2 mesg 031: V-2-31: vx_disable - /dev/vx/dsk/mydg/vol1 file system disabled
Sep  1 06:23:03 myserver vxfs: [ID 702911 kern.warning] WARNING: msgcnt
3 mesg 037: V-2-37: vx_metaioerr - vx_inode_iodone -
/dev/vx/dsk/mydg/vol1 file system meta data write error in dev/block
0/265984


It seems VxDMP gets the I/O error at the same time as MPxIO  : I though
MPxIO would have conceal the I/O error until failover has occured, which
is not the case.

As a workaround, I increased the VxDMP
recoveryotion/fixedretry/retrycount tunable from 5 to 20 to give MPxIO a
chance to failover before VxDMP fails, but I still don't understand why
VxVM catch the scsi errors.

Any advice ?

thanks.






--
Sebastien DAUBIGNE
sebastien.daubi...@atosorigin.com  - +33(0)5.57.89.31.09
AtosOrigin Infogerance - AIS/D1/SudOuest/Bordeaux/IS-Unix

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-- 
Sebastien DAUBIGNE
sebastien.daubi...@atosorigin.com - +33(0)5.57.89.31.09
AtosOrigin Infogerance - AIS/D1/SudOuest/Bordeaux/IS-Unix


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