fstab bug / SWAP does not mount after installing CentOS.
Yesterday, I finally got a VPS here at Linode
I chose CentOS as a distro. Here I did little re-arranging in the device setup.
In the Linode config profile, things are configured as follows:
/dev/xvda -> CentOS 5.0 Disk Image (Root partition)
/dev/xvdb -> Data (Database etc. goes here) - changed from SWAP (default)
/dev/xvdc -> SWAP
When I booted the Linode, I noticed that SWAP was 0 ! Then I checked fstab to see that SWAP was still pointing at /dev/xvdb ! (Changed it ofcourse).
Just to inform You guys, if someone else is running their Linodes without SWAP, because of customization to the device setup.
7 Replies
caker
Linode Staff
Technically this isn't a bug, since the distro wizard deploys your images expecting device a to be root, and device b to be swap. Editing your configuration profile doesn't automatically update your fstab.
-Chris
If it's "technically" not a bug - why have the option to change device-setup, if it does not reflect in the configuration once the distro has ben installed ?
Not to be harsh or anything, but as a new user - Isn't this very user-unfriendly ? (thought the device-setup, was to help the users / newbies, and not to complicate things).
In a user' world (my world from this point of view please try to understand me as a customer), this is a bug (technically or theoretically). If there is an option / possibility to change a config-parameter in the user-interface, but it does not "reflect" in the config-file once distro has been instaled, it must per defnition be an error according to common usability design practices ? or ?
Why should the option to change things (device setup) be in the Linode manager.
At the end of the day - I'm happy I found out that I did not have a SWAP assigned, and did the change to /etc/fstab manually. How many other users / newbies run without SWAP, because of this bug.
This post is NOT meant to offense anyone. Merely to pinpoint a "bug" / Irregularity.
I rest my case now.
/Anders.
@caker:
Hello,
Technically this isn't a bug, since the distro wizard deploys your images expecting device a to be root, and device b to be swap. Editing your configuration profile doesn't automatically update your fstab.
-Chris
I think you've mis-understood the options that the manager give you. Linode provide you with the virtual machine that you can configure however you want.
After you deploy a distro, it is entirely up to you how you set it up. Infact you dont even have to stick with the distributions that linode provide. You can re-roll your linode to have anything you want, Whilst a drive label/format might initially be 'swap' you could change that without updating the manager.
Some of us have multiple profiles in which we boot between that would put 'drives' in different locations. I certainly don't want the linode manager attempting to modify files on whatever my distribution may or may not be. The labels are purely cosmetic and don't always reflect what is there, so how would linode be able to tell which files to modify?
I assume your new to virtual machines, which might make this a little hard to understand at first. But you will find that most systems do not modify the OS when you change disk configurations. Vmware certainly doesn't, nor would i want it to.
I mean if you compare this to a physical machine, if you stick a new hard drive into your computer and that reorders your drive numberings, its up to you to change your config files to match, theres nothing that changes it for you. Why should it be the linode managers job to do that? Especially when it cant necessarily 'guess' what the drive is used for.
I think you will find the rest of the linode community does not see this as a bug, more how it is meant to work.
Altering your config profile is the approximate VPS equivalent of changing the hardware on a physical server. If you move disks to different controllers or add a new disk, you still have to edit /etc/fstab (or mount them by hand). Unlike physical disks, Linode images can be 'ready to use' but you can also use fdisk and the relevant format utility to install the weird filesystem of your choice, if you are that way inclined.
While Linode automatically fixes things like /etc/inittab to have the correct getty processes running, they can't really fix /etc/fstab - non-standard filesystems on raw images and users creating systems elsewhere and moving them to their Linode preclude this.
Edit: Internat beat me to it.
Against this background, I think it would be great for the Linode staff to put a little more effort into making the (already fabulous) Linode Manager a bit more n00b-friendly. At least there could be a "Help" button on each page, where all the functions are explained and the usual mistakes clearly noted. In the case of itarchitect, a short paragraph comparing the device setup to a physical computer and telling the user to manually update /etc/fstab would have saved him/her at least a few minutes of frustration.
When it comes to price, quality of products, and support, Linode is the best host I've ever been with. But as the web hosting world begins to take VPS's more seriously than ever before, n00b-friendliness could be a significant factor in Linode's competitiveness.
@itarchitect:
/dev/xvda -> CentOS 5.0 Disk Image (Root partition)
/dev/xvdb -> Data (Database etc. goes here) - changed from SWAP (default)
/dev/xvdc -> SWAP
So where do you want your "Data" image mounted? We don't know from looking at your post, and neither does the Dashboard.
Also, what if your / was formatted with reiserfs or xfs? The host is expected to know how to mount these partitions? Or what if the file system is ext4? I don't think the host's kernels are new enough to work with that.
The point of that ramble: The images work with the default config provided by the Distro wizard. You went beyond that configuration, so you know you changed something, so you should fix it. You can't assume that every variable in an environment as flexible as Linode can be accounted for.