Hi,
I have a RAC installation on 2 solaris 11 nodes. (With ASM)
Disks' mpath are managed by EMC Powerpath on both nodes.
I want to migrate mpath software to Solaris multipath without downtime.
My plan is first migrate node1 to solaris mpath, then after some days migrate node2 to sol.mpath.
My question is, is it possible to run RAC's ASM disks with different mpath softwares?
For some days node1 will run with solaris mpath and node2 with Emc powerpath...
Thanks..
I'd be tempted to take the outage on both nodes of the RAC if I was you, there is always a risk of something unexpected when you "mix and match" so caution is the way forward here.
It has been many years since I have used EMC powerpath and it was MPXIO that replaced it in my case.
Changing to MPXIO is very straight forward with only minor differences to the stmsboot command.
If there is a successful outcome the disk naming will change when viewed from format you will see the devices listed as below fir internal disk;
Code:
root@fvssphsun01:/export/home/erdr/logs# echo | format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c0t5000CCA0561F502Cd0 <HITACHI-H109060SESUN600G-A690-558.91GB>
/scsi_vhci/disk@g5000cca0561f502c
/dev/chassis/SYS/SASBP/HDD0/disk
1. c0t5000CCA056200D00d0 <HITACHI-H109060SESUN600G-A690-558.91GB>
/scsi_vhci/disk@g5000cca056200d00
/dev/chassis/SYS/SASBP/HDD1/disk
2. c0t5000CCA05620DAE4d0 <HITACHI-H109060SESUN600G-A606 cyl 64986 alt 2 hd 27 sec 668> solaris
/scsi_vhci/disk@g5000cca05620dae4
/dev/chassis/SYS/SASBP/HDD4/disk
3. c0t5000CCA0561F5014d0 <HITACHI-H109060SESUN600G-A690-558.91GB>
/scsi_vhci/disk@g5000cca0561f5014
/dev/chassis/SYS/SASBP/HDD5/disk
And for SAN disk you should see;
Code:
4. c0t600507680C80827800000000000004A3d0 <IBM-2145-0000 cyl 51198 alt 2 hd 256 sec 128>
/scsi_vhci/ssd@g600507680c80827800000000000004a3
5. c0t600507680C808278000000000000049Ad0 <IBM-2145-0000 cyl 6398 alt 2 hd 256 sec 64>
/scsi_vhci/ssd@g600507680c808278000000000000049a
6. c0t600507680C808278000000000000049Bd0 <IBM-2145-0000 cyl 1278 alt 2 hd 256 sec 64>
/scsi_vhci/ssd@g600507680c808278000000000000049b
7. c0t600507680C808278000000000000053Ed0 <IBM-2145-0000 cyl 3838 alt 2 hd 256 sec 64>
/scsi_vhci/ssd@g600507680c808278000000000000053e
As I said earlier, I would take the outage to do this work and do both nodes together - I know that there is likely to be push back on that scenario. But balancing the potential risk seems like a sensible thing to do here, running two disk control subsystems is increasing the risk. In the event that there is some kind of clash between the pathing software do you have a plan to resolve, i.e a set of snapshots to roll back or something similar.
Regards
Gull04
------ Post updated at 01:31 PM ------
Hi vlkkck,
OK, having had a bit of time to have a look and nab a DBA. There are a number of points to be aware off;
Oracle RAC is active/active so both sides should be the same mult-pathing.
The system could contain a number of combinations of types of disks - in addition to ASM
The ASM disks may be tagged with the "emcpower" ID's.
Management disks may exist, traditionally these would be migrated to new disks.
All in all this could turn out to be a fairly major piece of work, so there would have to be a bit of research. If you are planning to remove power path, there is a need to check how the ASM disks are identified.
Regards
Gull04
These 3 Users Gave Thanks to gull04 For This Post:
Well i would start by installing (if my infrastructure allows this) a same solaris 11 instance with couple of luns, not related to original RAC.
Present couple of luns, create asm or simple filesystem over those disk, and then switch from EMC to native to see effects
If you can, clone/snapshot the entire monster using storage methods in a network isolated environment to give it a shot.
In theory, ASM doesn't care which multipath software is used.
It's just a symlink to disk slice if configured per docs.
So, if you failover and use only single node, reconfigure the multipath on other box and create exact same symlinks to devices used on EMC devices before, stuff should just magically work.
Disk label should stay the same and sliceN used in ASM configuration should be the same, no mater which multipathing software is used.
But to put a small disclaimer, from all the storage stuff i have not worked with EMC or their multipath software.
As i've been reading the powerpath stuff will create /dev/emcpower* or similar device files, on which it will intercept the IO and balance it to appropriate disks devices below.
Using commands provided by that software, list the mapping to devices below.
Check what ASM has defined inside configuration for disk match (ASM_DISKSTRING).
Looks fairly transparent to change, but i would try it first in non-volatile environment...
Once ASM see's the disks it will sort it's self out and will correctly identify all the disks, I know this because two years ago I did extensive testing - on AIX and Solaris where the disk ID's were deliberately mixed up. In all cases ASM sorted everything out, even when the physical disk ID's were swapped around on multiple disks but the underlying multi-pathing always remained the same.
To accomplish this there was a manual intervention, whilst bringing up ASM - DBA's did that bit. I would completely agree with you that if the environment allows this should be tested, I would assume that there would be a Test/Dev setup of some sort to do this on.
Each has a unique identifier in header.
For instance on Linux or HPUX, if you run vgscan, whatever names are there the import will work if all the disks are there with same VGID.
ASM works the same, after it can see the disks using ASM_DISKSTRING.
Using MPXIO the path to be used in software won't actually be /scsi_vhci/... but rather /dev/[r]dsk/c0t ...
... being storage controller wwn + LUN ID
Check the correlation with ls -lrt /dev/rdsk/<some fc disk>
And doing luxadm display /dev/rdsk/...s2
Numbers will be matched.t.
This is what i do not like about linux multipath and those default /dev/sd[abcefg...]
But you can always rewrite the multipath configuration file to create mapper device files in similar fashion
Thank you for all answers..
I used solaris mpath for 5 years, and its very easy to manage and activate it with stmsboot. But I moved to another job and my new system is using emc powerpath which has some pros and cons.
As a old fashioned admin I dont want to see hundreds of disks with format command, but with emc powerpath I see (number of LUNS * number of paths) disks (in my case its over 1500 disks ) and it increases the complexity of the system.
So next week I will migrate one node of my test DB to solaris Mpath and see what will happen. I think different mpaths will not work properly. I will share my experiences about migration.
I need to know information regarding the softwares/applications that are installed on my Solaris server and also its end of life or support information.
Can some one help me how to get these details please...
Thanks (3 Replies)
Hi Folks,
Please advise for FTP client softwares like winscp we use mostly to transfer the files to other unix box machines but any ftp software which in logs will also generate and show the unix commands parallely for ex if I create a directory graphically through ftp software then it will list... (1 Reply)
Which distro uses lowest system resource (when installed on hard_disk/usb.) where I can install software from Debian OR Ubuntu repository?
I found Quelitu which is based on Lubuntu, but uses less memory as given on their site. There are lighter distros but most of them are based on Slackware. I... (0 Replies)
hi everyone,
We have rac system which has two sun solaris M5000s and two oracle 11gR2 databases respectively. Also , we have unix codes on one rac and these unix codes extract txt files for external tables during first step of ETL.
We run our unix codes using Util.RunThis java code and... (10 Replies)
I just installed solaris 10 x86, i was wondering if there are softwares out there that i can install on my system to make my system more lively
eg photo browser etc, also i was trying to play dvd movie with totem movie player when i had error "could not determine stream type" (2 Replies)
I need list of 3rd party softwares installed in a Unix server (eg: Fedora / RedHat). I know if they are system supported format (like rpm format for fedora/redhat, pkg format for debian/ubuntu etc) we can list them by system specific commands ($ rpm -qa). But how to list the softwares installed... (3 Replies)
Greetings to Everyone, iam a new unix learner , can anyone tell me how to install softwares and utilities in unix, (comparing with windows installation) . in windows we use to install softwares like executing a "exe" file with "next,next....finish."
Give me some details abt "how the setup... (1 Reply)
I am connected to Internet on newly built solaris machine. I have downloaded putty.exe on Desktop and then when I double clicked it ... It gave some errors of 'Associating Application...' what is all that? and How to run Putty now? I dont remember... but may be I did something on association window... (1 Reply)
Hi all,
how to find 3rd party softwares like Oracle,phpldapadmin,Citrix etc (other than packages) which are installed on a linux box.
Please guide me to get this info'n on LINUX/SOLARIS.
Thanks in advance,
Uday (0 Replies)
11-05-2018
