Oracle: Unbreak my Linux Heart

If you manage a few dozen servers or more, maintain a couple of applications or even websites, you owe it yourself to use some kind of Version Control Systems . Something like CVS, SVN or maybe even Git. Alternatively, you can use something like cfEngine to keep all servers configured similarly. However, CVS or SVN can store working versions of all important in one place and provide you will roll-backs if worse comes to worst. Application servers create little config files like crazy and getting a release frozen into SVN, using a subversion tag, can be a life saver at times.

There was a message from Michael Brown on the Dell PowerEdge mailing list, that I thought is important enough to repeat here as many people may not know about that list. Dell has an active OpenManage infra setup for Linux to help monitor and manage their hardware. As we have their 2950s, I'm monitoring that list. "After several months of work, I am ready to announce a bèta period for the Dell Community Linux repository at http://linux.dell.com/repo/community . When complete, this repository will be the replacement for the current software repository. Please read the details on the repository homepage. I will be running a two week beta period to ensure that the repository is functioning properly. After two weeks, I will redirect software repo bootstrap so that new installs will use the community repo. And two weeks after that, I will redirect all current software repo users to the community repository. Early this year I asked the community if people would be willing to submit...

While on the subject, I found instructions on Using Device-Mapper Multipath in Red Hat's RHEL 4 update 6 (4u6). May help getting it to work with 4u5 too, or help decide if you should update... Update: here is a guide for RHEL 5, update 1 (PDF)

I got a mail today from another group working with Linux servers on Dell PE2950's. They have HP EVA boxes as their SAN, instead of our EMC DMX-3/4, and wanted to know how we got multi-pathing to work in Oracle's Enterprise Linux 4, update 5. They had heard that it was terrible and were thinking of using RHEL/OEL 5u2 instead. I told them, we were using PowerPath for this reason, and because EMC would only support us iff we used PowerPath. dm-multipath was not supported. Hmmm. Fair enough... While dm-multipathing is available in OEL 4u5, you have to go through some tricks to get it to support your root volume over dm-multipath. TuxyTurvy has instructions and people report it works. The trick he uses is to make a custom initrd image. Another solution may be to use HP StorageWorks for Linux or HP's own dm-multipath . Update: We going a different route... We'll install ESX 3.5 on the Dell servers and install Linux in VMs only, virtualizing the whole setup. ESX is compatibl...

I have up2date setup for my servers to update most packages but ignore kernel updates as well as oracleasm -related updates. Kernel updates break things and must be done manually, when needed. However, I prefer using yum over up2date. But until now I did not find an easy way to tell yum to ignore updates on some packages. An old Duke mailing list had an improved man yum text that eluded to add multiple exclude=package* statements to the repos in /etc/yum.repos.d/ . Thanks Duke! Here is my example yum repo configuration with the excluded packages: [el4_patch]name=Oracle Enterprise Linux - $releasever - $basearch - patchbaseurl=http://uln.example.com/yum/EL4/$releasever/patch/$basearch/exclude=kernel*exclude=oracleasm*gpgcheck=1enabled=1 Update: something is still not right for it just upgraded the kernel anyway. Update2: When I moved the 'exclude' lines before the 'enabled' line, the yum update process does indeed ignore kernel updates, as expected. Before, I had the...

I accidently did an update of a test server using ' yum update ', realizing I'd get a new kernel but forgetting the new kernel would break my PowerPath setup. It's EMC's software for getting multi-pathing and we use version 5.0.0 (EMCpower.LINUX-5.0.0-157.rhel). I should have used up2date because it knows how to update and skip undesired packages, such as the kernel... Oh well. *Nix hacks had some tips to fix PowerPath after kernel updates . You simply need to reinstall the package and force a replacement.

Oracle has updated the instructions on how to setup a local yum repository for Oracle's Unbreakable Linux program. It's a bit shorter, clearer and the channels are better explained than before. However, if you want have a yum repo mirror that can also utilize ISO images as well as a set of custom RPMs, not normally in the repository, be sure to check out DAG's mrepo instead. Using mrepo, you can have a yum repo, a dir with local, custom RPMs for specific apps, as well as plain straight ISO images. Update: their yum population script was updated again late December.

Found a useful post on the Dell PowerEdge mailing list . There was a discussion to get DRAC5 and Firefox working, especially on Linux but for Windows its also useful. Mark Watts finally gave the correct instructions . Reports are that FF 1.5 also works but 3.x still does not. [Update: When using DRAC v1.40 , there are supposed to be Java plugins for Firefox 3.x] [Update2: I can confirm that DRAC5 v1.40 works fine with FF2+ in Windows and Linux. Haven't tried OS X yet.]

Liquidat has a tip for when rpm/yum seems to hang up and nothing but a reboot will work. Just delete /var/lib/rpm/__db* and try again. Hmmm, wish I'd known about that a few months ago. Seems a complicated issue with rpm, but rawhide appearantly has a fix for it.

A discussion on the Dell poweredge mailing list on a Dell Warranty check , resulted in a small tidbit to discover the Dell service tag from the Linux command line. :) Using dmidecode | grep -i serial , with or without using sudo or changing to root, you get the service tag of your bare metal Linux server. Using this service tag, you can query Dell support to find out if you still have a warranty.

On and off we have timekeeping issues with certain applications in Linux VMs. Now I know this is a common problem and nothing new. Bottom line is that you should leave the time keeping to VMware Tools and sync all ESX hosts to the same time source via NTP. However, it still can go wrong. There is a whole list of sources with tips, hints and solutions, but your mileage may vary. I was just pointed to a very detailed white paper by VMware that may help to solve your application specific problems, whether in VMware, Xen or Hyper-V. Check the 27 page PDF : " Timekeeping in VMware Virtual Machines " Update: Read the VMware KnowledgeBase on time keeping in Linux VMs or search for KB ID# 1006427.