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serviceguard in linux vs hpux

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anat heilper
Frequent Advisor

serviceguard in linux vs hpux

Hi,
I've worked with serviceguard hpux for a while, and now we move to Linux Itanium with serviceguard. Are there major differences between the different plarforms?
Thanks, Anat
7 REPLIES
Steven E. Protter
Exalted Contributor

Re: serviceguard in linux vs hpux

Shalom,

The only differences I have seen have to do with LVM rules and installation. A disk can't belong to two volume groups under hp-ux, it can be carved into more than one volume group under linux.

Everything else thus far has been very similar, xinetd instead of inetd, nothing huge.

configuration scripts are portable to some degree, once disk path and volume group issues are worked with.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
melvyn burnard
Honored Contributor

Re: serviceguard in linux vs hpux

Major differences?

1) Use rpm to install instead of swinstall

2) LVM does not have a vgchnage -a e option

3) To have create a standby LAN you need to create a bond between two lans.

4) Files are in slightly different places, depeneds on which flavour of Linux you use.

5) set up of disks is differnet, but you still end up using LVM with the standard LVM constraints

6) You cannot have a cluster lock disk, it must be a Lock Lun, otherwise use a QS.



Other than that it is really down to the management/administration pof a Linux server compared to a HP-UX server



My house is the bank's, my money the wife's, But my opinions belong to me, not HP!
anat heilper
Frequent Advisor

Re: serviceguard in linux vs hpux

Hi,
From the documentation that I read, I saw the following paragraph regarding exclusive access:
As of release A.11.16.07, Serviceguard for Linux provides functionality
similar to HP-UX exclusive activation. This feature is based on LVM2
hosttags, and is available only for Linux distributions that officially
support LVM2.

which versions of Linux support that?
Steven E. Protter
Exalted Contributor

Re: serviceguard in linux vs hpux

Shalom again:

2) LVM does not have a vgchnage -a e option

It does have an option. It just doesn't work like HP-UX and prevent mount, making it functionaly USELESS.

Also note that SG on Linux does support GFS and that product is not available on HP-UX. It seems to be a pretty good product.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Serviceguard for Linux
Honored Contributor

Re: serviceguard in linux vs hpux

LVM2 is available with SLES9, SLES10, RH4 and RH5. Steven is correct in that this is not as easy to use as the "-e" option but is does provide significant protection.

GFS is not currently supported in Integrity servers, just proliants.

Other differences are in "add on" products.

MetroCluster on HP-UX - CLX on Linux Very similar functionality but not exactly the same (e.g. CLX is only EVA and XP).

No CC on Linux.

No SGeRAC on Linux.

Different toolkits.

But your experience in HP-UX will leverage easily to the Linux version. The code base is the same with most other differences based on operating system differences.
John Bigg
Esteemed Contributor

Re: serviceguard in linux vs hpux

Just to add to this, firstly one of the biggest differences between SG/UX and SG/LX is in the area of lan monitoring.

With SG/UX the lan monitoring is done within Serviceguard with Serviceguard polling the lans and checking the status and lan statistics. If a failure event occurs then Serviceguard is the one who performs a lan switch.

With SG/LX, Serviceguard relies on the bonding driver to monitor the lan interfaces and simply uses ioctl's to read the status back. You cannot configure a standby but you have to use the bonding driver to give you equivalent functionality.

With regards to activation on Linux using LVM2 this is not exclusive activation as you get on HP-UX but is far from useless and is a major improvement.

If you are familiar with VxVM integration in an HP-UX cluster (base VxVM not CVM) the functionality is similar to this. SG/LX uses host tags to prevent accidental activation of a volume group on 2 nodes at the same time. Yes, it is possible to manually override the host tags and activate a volume group on multiple nodes (with possible corruption if filesystems are involved) but you cannot do this accidentally if you have things configured correctly.
Unix Team_6
Advisor
Solution

Re: serviceguard in linux vs hpux


As a big user of Serviceguard on HPUX and now Redhat Linux on Proliants weve found the major differences are;

1. Cant use LVM mirroring on Redhat. not supported yet (by Redhat - even in RH5 its still pre-release). Have to use mdadm software mirroring - works fine but takes a bit of getting used to.

2. When shutting down a package on Linux it can force deactivate the vg even though the app shutdown failed - and so the pkg shutdown says successful when it wasnt really. On HPUX it would show as failed. With a bit of scripting easy to fix though.

3. On Redhat you are "strongly advised" to fsck regularly and the filesystems are setup by default to do this every few months. this can cause failover times to go from a few mins to 30-40 mins for big VG's ! Redhat strongly advised us not to remove it. Only solution is to run GFS on both nodes so no need to fsck on the 2nd node if node A fails. This makes failover times a lot more than on HPUX unless you use GFS or disable the regular fsck checks.

Weve found SG on Linux (redhat) to be almost exactly the same as on HPUX. All the commands and behaviour the same (apart from the above). I highly recommend it! Its a hell of a lot cheaper than running it on hpux or Itanium/PARISC.