Solved Is it important to have a fixed size of VM disk-image-file to significantly increase performance if the host disk is an SSD-disk?

jeltoesolnce

jeltoesolnce

Hello. I have old dellserver (Xeon 1230 V.3, 32 Gb, 256 SSD Samsung EVO) for database/application server on guest Ubuntu. Get I significantly increase, if I change hdd type on 'fixed'?
 
Fixed-size of hhd
P.S. As I understood, disks are fixed-size and dynamically expandable size. Sorry my English.
P.P.S. I read and I know that fixes-size hdd increase performance for guest system, but how much?
 
Yes. The VM has a disk. The disk can be permanent or dynamically expandable. As mentioned, a constant disk size increases the performance of the guest system. However, if the disk is an SSD, then accessing it is fast enough. For this reason, does it make sense to clone the disk and put it in a "fixed size" state?
 
I don't know how much slower dynamically expandable disks are, but it should be really easy to test:
- make two new disks for the VM
- one expandable
- one not
- do a write benchmark (be careful that the benchmark has an fsync(2) at the end)
 
jeltoesolnce said:
I wanted to find out "for free" so as not to do it myself :).
But thank you for your time and your answers.
Click to expand...
Well, I can't give you any better *real* answers (though I suspect there's not much of a tradeoff any more with faster SSDs), but your "for free" adminssion gave me quite the best rumbly-tummy laugh I've had in a while. Rumbly-tummy was chosen especially in honor of your avatar.
 
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