For most people, this is an acceptable risk due to space-vs-cost reasons (ie if this is really important there will be a budget to do it correctly) - and because, as they say, backups are good, right?įor me, the single reason to not use LVM is that disaster recovery is not (or at least, was not) well defined. If your filesystem spans two disks, and either of them fails, you are probably lost. One disadvantage of LVM used in this manner is that if your additional storage spans disks (ie involves more than one disk) you increase the likelyhood that a disk failure will cost you data. The advantages of LVM include the fact that you can add more storage to existing filesystems without having to move data around. In most situations, this performance hit will be practically unmeasurable. With respect to performance, LVM will hinder you a little bit because it is another layer of abstraction that has to be worked out before bits hit (or can be read from) the disk. LVM, like everything else, is a mixed blessing. Make a partition with LVM, test it, wipe that out and (in the same place, to keep other factors identical) create a plain filesystem and benchmark again.
![ubuntu volume manager ubuntu volume manager](https://www.howtogeek.com/wp-content/uploads/2011/01/pvdisplay.png)
But mostly, the impact should be very small.Īs for the last: how can you test? The standard disk benchmarking tool is bonnie++. Oh, and using LVM snapshots degrades performance (and increasingly so with each active snapshot). And make sure you're not using old kernels subject to bugs like this one.
![ubuntu volume manager ubuntu volume manager](https://i.ytimg.com/vi/xK7zzUkS_y0/maxresdefault.jpg)
You want to make sure the LVM blocks are aligned properly with the underlying system, which should happen automatically with modern distributions. There are cases where LVM can cause performance problems. (Since it has to happen anyway, doing it a bit differently is a negligible performance hit.) When it comes to actually writing the file, the bits take as direct a path to the physical media as they would otherwise. When LVM is in use, that lookup is changed, but that's all.
#UBUNTU VOLUME MANAGER DRIVERS#
The kernel already needs to have a mapping (or several layers of mapping actually) which connects high level operations like "write this to a file" to the device drivers which in turn connect to actual blocks on disk. From the userspace point of view, it looks like another layer of "virtual stuff" on top of the disk, and it seems natural to imagine that all of the I/O has to now pass through this before it gets to or from the real hardware.īut it's not like that. Just be aware that enabling it can cause data loss in the event of loss of power-data that is in the cache but not yet permanently written to the disk will disappear when power gets cut.LVM is designed in a way that keeps it from really getting in the way very much.
![ubuntu volume manager ubuntu volume manager](https://www.linuxlinks.com/wp-content/uploads/2018/11/LXQt.jpg)
This is because one write event is quicker than many write events when the amount of data to be written is of the same size. Enabling write cache can improve your drive's performance because it forces the drive to put data that should be written into its cache first, and once it fills up it gets permanently written onto the disk. You can apply write cache settings under the Drive Settings option to speed up your drive. If the system can't find anything wrong, however, then something else might have caused whatever problem you're facing. If it does find some problems, there's probably not much you can do to fix it, but at least you know it's a hardware issue.
![ubuntu volume manager ubuntu volume manager](https://i.stack.imgur.com/6Wwmb.png)
If you think your drive has been behaving strangely, you can take a look at the SMART Data & Self-Tests to see if the system can detect any irregularities with the disk. If you are curious about just how fast your drive really is, you can benchmark it with Benchmark Disk to see how fast your read and write speeds are, as well as your access time (the time it takes for the drive to locate a file).