Fedora and LVM

Posted Nov 3, 2012 18:08 UTC (Sat) by Cato (guest, #7643)
In reply to: Fedora and LVM by marcH
Parent article: Fedora and LVM

Actually I've used LVM a fair bit on various Linux systems, and got burnt by it, including significant data loss (write barriers not being implemented, mostly). Then I was very anti-LVM, now I have a more balanced position, in my view: it's good for servers where high uptime is needed, but overkill for most desktops where raw partitions and Gparted are safer and easier.

I am about to extend use of LVM on one server where I need to add a large disk, and want a single huge LV across several disks. (Something that the raw partition model can't deliver).

However, on a laptop/desktop I would not use it (perhaps for a desktop to span disks, but not within a single disk.)

I would not have spent this much time ranting about LVM if I had not used it quite a lot...

Fedora and LVM

Posted Nov 3, 2012 20:39 UTC (Sat) by dlang (guest, #313) [Link]

> t's good for servers where high uptime is needed,

being a bit picky here.

servers don't need high uptime, the services they provide need high availability time. This is not the same thing (even though it sounds like it should be)

pushing for high uptime on a single server will get you quite a ways towards high availability time, but then you hit a wall and you need to move to cluters of machines. Once you move to clusters of machines, the need for high uptime on a each individual server drops dramatically.

While the clustering adds complexity, this now allows for management of the indivudal servers to be much simpler as you are no longer racing the clock for each change. This (usually) results in a very dramatic improvement in service availability, and a dramatic _decrease_ in _unplanned_ server downtime. there is more _planned_ server downtime, but it's the unplanned downtime that your customers notice.

There is a small (and shrinking) pool of application types that are really hard to cluster and really do need high uptime, but far fewer than you would think.