Update the kernel on Rackspace Cloud Server

To change the kernel on a server hosted on Rackspace (using Debian) you just need to use aptitude as normal as always, but, If you want a 3.x kernel, it's probably that you will get this error on your dmesg:

[    9.825536] blkfront: barrier: empty write xvda op failed
[    9.825553] blkfront: xvda: barrier or flush: disabled
[    9.825563] end_request: I/O error, dev xvda, sector 11528
[    9.825570] end_request: I/O error, dev xvda, sector 11528
[    9.825577] Buffer I/O error on device xvda1, logical block 1185
[    9.825584] lost page write due to I/O error on xvda1
[    9.825602] Aborting journal on device xvda1.
[    9.828269] EXT3-fs (xvda1): error: ext3_journal_start_sb: Detected aborted journal
[    9.828284] EXT3-fs (xvda1): error: remounting filesystem read-only

Then, apparently is a well know bug in Xen: debian bug and xen list then the solution is to add to /etc/fstab just like this:

/dev/xvda1 / ext3 defaults,errors=remount-ro,noatime,barrier=0 0 1

Well, that's the only needed to fix it. Hope it help to someone.