time since since I have shared XenServer tips with our blog community. Oddly enough, I stumbled upon a buried design in my files. It was 30-JUN-2014 dated and titled "A hat-tip". In this way, a solution for a customer should be made available, which requires that I give a reason and solution to a problem they had experienced.
Because this tip can be very useful, I wiped the dust and clean the contents. In advance, I would like to say: "Thank you." How, with the release of XenServer 6.5 recently behind us, and with the title of this article refers FSCK, inquiries stands, requests or comments for non-EXT file systems
http://discussions.citrix.com/forum/1289 If you contribute a look at open source XenServer here -feature-requests-and-suggestions /
take:
http://xenserver.org/overview-xenserver-open-source-virtualization/source-code.html
Setting the Stage
XenServer uses the Extended File System (EXT), which has been since the late 190s, for his Domain0. During installation, you can also choose to use EXT for the local storage repository, instead of the default LVM scheme. It is only natural, based on the kernel in my humble opinion that EXT2 / 3/4 still remains also with every Linux based distribution. How NTFS, it is a journaling file system with some pretty cool perks. The resilience in the face of data recovery / integrity is one of my favorite two functions, because it is not so CPU intensive than alternative file systems.
Thus, as XenServer Administrator, you may or may not know that the EXT file system - by default - to vote set itself every 180 days or after an unclean dismount detection etc.
Here's what the means for you
at some point - it was a power failure or finally get to run update - a XenServer administrator may notice a longer than normal boot process. This lengthy boot process is probably the result of the acting EXT because the system has detected that more than 180 days have passed. Or in the prime example, power was lost to a facility and had everything to be powered from the last "unclean" state.
At this point we have a 10TB picture, EXT-based storage repository coming online, the file system was mounted unclean due to the power outage. XenServer Dom0 the will to recognize and determine that a file system check is required, the problem.
The problem
Many administrators would never before finally loading the kernel the FSCK (file system check) notice Check disk integrity. In the example I have provided, you never fill FSCK perhaps his job to check the file system. As a result, the left FSCK our system in a READ-ONLY state. This is hardly usable for XenServer purposes, right
Here is the cause of this problem is:
- The kernel or dom0 has a standard amount of memory in /boot/extlinux.conf[1945004ihmzugeordneten] - If you command line access have to XenServer, well, welcome to Dom0! You are now in user space
- Any command that you or the kernel, and so causes the system will lead you to use this memory and, if necessary, the 512MiB swap space: ping, ssh, cat, ls , etc.
the solution.
Since the relevant storage repository was doing a 10TB, EXT-based file system, FSCK requires more memory, his work. Overlooking /boot/extlinux.conf in the fallback kernel we increased the XE and XE SERIES kernel memory for dom0 from 752m to 2048M (see below, in bold, for dom0_mem =):
| Before: /boot/extlinux.conf Label xe attach label xe series After: /boot/extlinux.conf label xe label xe series [1945004attach] # XenServer (Serial) |
|---|
So, with the amount of memory assigned to dom0 which fSCK, we start as use user-space program again and presto -.?
FSCK finished, everything was in clock, and XenServer was ready in production to be back
Why not the fallback kernel
This case I would - to leave the primary boot kernel, all alone. But the system in this case requires back online as quickly as possible to be. , Restarting 10TB can restart in the alternate kernel to change its dom0 values again in the fallback kernel FSCK scan data, to undo the changes, and in the primary kernel reboot would not have been a speedy recovery.
More importantly, for this customer Dom0 had the memory allocation to be increased during the next maintenance window, so yes - two support tickets dissolved in a
I hope this information is of benefit to our community, if you find yourself in this situation! .. If you find yourself in this situation
I this information hope of benefit to our community is
-jkbs | @xenfomation | XenServer.org Blog
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