Jump to content
RESET Forums (homeservershow.com)

Can you install an O/S on a MicroSD card.


Recommended Posts

I just think there would be too much IO activity on an SD card.


Agreed. They're not built for it. Interestingly though, there is a Compact Flash card that is built to have an OS installed on it, even Windows. It's basically an SSD in a Compact Flash jacket. It's used primarily for embedded systems.

Link to comment
Share on other sites

Yes you can very easy. In my both my HP Microserver Gen8 I have a MicroSD (4GB and 16GB) with a fully functional Fedora 20 Live for system rescue purposes.

 The installation is very easy just follow the https://fedoraproject.org/wiki/How_to_create_and_use_Live_USB. There is no diference between a MicroSD and a USB drive from this point of view.

  Even a 4GB MicroSD is enough, 2GB can be too small.

Link to comment
Share on other sites

For those purposes, georgio, it works really well. jmwills & I are just saying not to run an OS like Windows on it. I might run the WHS2011 install ISO from one, particularly to Restore the OS from a backup.


And agreed, there is no difference between an SD and USB drive.

Link to comment
Share on other sites

  • 10 months later...


I am currently using my gen 8 booting direct to Xpenology on a USB 2 flashdrive, I thought it might be quicker on a USB 3.0 but it wouldnt boot.

I wonder if it would be any speed improvement with class 10 micro sdcard. and what I would have to do to change to that is so.

many thanks


Link to comment
Share on other sites

The biggest problem with running an OS from an SD card isn't that it will wear out too quickly - I run various ARM machines off SD cards and I have yet to have one expire as a consequence. By far the biggest problem is performance. Random write performance of an SD card is typically 1-5% of a low end mechanical SATA drive. Some SD cards are much better than others, but there is no distinct pattern to which ones - one model of one brand might be good, another model of the same brand might be attrocious.


There are some workarounds for this:


1.1) nilfs2

Pros: This file system is log-structured (append only), which means all writes are always sequential. Since SD cards are good at sequential writes, the performance is generally quite good.

Cons: The way space is reclaimed is that a chaser thread reaps the oldest written data, prunes out deleted data, and re-writes the remaining data to the head of the device. That means that a lot of data writed happen needlessly, causing potentially large anmount of write amplification and increased flash wear over time.


1.2) ZFS

If you use ashift=13 (8KB sectors) and sync=disabled, the performance with ZFS is reasonably bearable. This is what I use on all of my ARM devices.


3) Put /tmp, /var/tmp, most things under /var/cache and similar on tmpfs


It all merely helps make the most of a very raw deal, but it makes SD performance bearable. In general most of what hits the rootfs on a typical server is logging. As long as this isn't too heavy, and all of your heavy I/O is happening on real disks, it will probably be OK.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...