Just a few days ago I finally got a new server to replace a good old friend of mine which has been keeping my data safe since 2005. I was literally dying to get it up and running and move my data over when I realized it had been 8 years since I last setup dmcrypt on a server I only had ssh access to, and had no idea of what best current practices are.
So, let me start first by describing the environment. Like my previous server, this new machine is setup in a datacenter somewhere in Europe. I don't have any physical access to this machine, I can only ssh into it. I don't have a serial port I can connect to over the network, I don't have IPMI, nor something like intel kvm, but I really want to keep my data encrypted.
Having a laptop or desktop with your whole disk encrypted is pretty straightforward with modern linux systems. Your distro will boot up, kernel will be started, your scripts in the initrd will detect the encrypted partition, stop the boot process, ask you for a passphrase, decrypt your disk, and happily continue with the boot process.
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Have you ever been lost in conversations or threads about one or the other file system? which one is faster? which one is slower? is that feature stable? which file system to use for this or that payload?
I was recently surprised by seeing
ext4 as the default file system on a new linux installation. Yes, I know,
ext4 has been around for a good while, and it does offer some pretty nifty features. But when it comes to my personal laptop and my data, well, I must confess switching to something newer always sends shrives down my back.
Better performance? Are you sure it's really that important? I'm lucky enough that most of my coding & browsing can fit in RAM. And if I have to recompile the kernel, I can wait that extra minute. Is the additional slowness actually impacting your user experience? and productivity?
Larger files? Never had to store anything that
ext2 could not support. Even with a 4Gb file limit, I've only rarely had problems (no, I don't use
FAT32, but when dmcrypt/ecryptfs/encfs and friends did not exist, I used for years the good old
CFS, which turned out to have a 2Gb file size limit).
Less fragmentation? More contiguous blocks? C'mon, how often have you had to worry about the fragmentation of your
ext2 file system on your laptop?
What I generally worry about is the safety of my data. I want to be freaking sure that if I lose electric power, forget my laptop in suspend mode or my horrible wireless driver causes a kernel panic I don't lose any data. I don't want no freaking bug in the filesystem to cause any data loss or inconsistency. And of course, I want a good toolset to recover data in case the worst happens (fsck, debug.*fs, recovery tools, ...).
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