In this part I will discuss a possible solution to a problem I encountered several times already – failure to understand XenServer use of LVM, but first – a little explanation of the topic. XenServer makes extensive use of LVM technology in order to support the storage requirements of virtual disks. It is being utilized…
DRBD is a low-cost shared-SAN-like solution, which has several great benefits, among which are no single point of failure, and very low cost (local storage and network cable). Its main disadvantages are in the need to constantly monitor it, and make sure it does what’s expected. Also – in some cases – performance might be affected greatly….
A friend of mine made a grieve mistake – partition a disk containing Linux LVM directly on it, without any partition table. Oops. When dealing with multi-Tera sized disks, one gets to encounter limitations not known on smaller scales – the 2TB limitation. Normal partition table can contain only around 2TB mapping, meaning that to…
Linux LVM is a wonderful thing. It is scalable, flexible, and truly, almost enterprise-class in every details. It lacks, of course, at IO performance for LVM snapshots, but this can be worked-around in several creative ways (if I haven’t shown here before, I will sometime). What it can’t do is dealing with a mixture of…
When one wants to achieve fast provisioning of virtual machines, some solutions might come into account. The one I prefer uses Linux LVM snapshot capabilities to duplicate one working machine into few.
This can happen, of course, only if the host running VMware-Server is Linux.
LVM snapshots have one vast disadvantage
Modern Linux LVM offers great abilities to maintain snapshots of existing logical volumes. Unlike NetApp “Write Anywhere File Layout” (WAFL), Linux LVM uses “Copy-on-Write” (COW) to allow snapshots. The process, in general, can be described in this pdf document. I have issues several small tests, just to get real-life estimations of what is the actual…
