TIP and HINT forget SSDs with LVM unless of enterprise level especially if you are going to use/implement the thin provisioning
How to identify an SSD of enterprise level: it costs from 1,00 euro per gigabyte up to 1,50 euro per gigabyte Kind regards Roberto Gini Technical Manager @ www.RecuperoDatiRAIDFAsTec.it Ottieni BlueMail per Android Il giorno 14 ott 2022, 21:50, alle ore 21:50, Roger Heflin <[email protected]> ha scritto: >What is the underlying disk hardware you are running this on? >virtual, spinning, ssd, nvme? > >On Thu, Oct 13, 2022 at 2:01 AM Pawan Sharma ><[email protected]> wrote: >> >> adding this to lvm-devel mailing list also. >> >> Regards, >> Pawan >> ________________________________ >> From: Pawan Sharma >> Sent: Wednesday, October 12, 2022 10:42 PM >> To: [email protected] <[email protected]> >> Cc: Mitta Sai Chaithanya <[email protected]>; Kapil Upadhayay ><[email protected]> >> Subject: LVM2 : performance drop even after deleting the snapshot >> >> Hi Everyone, >> >> >> We are evaluating lvm2 snapshots and doing performance testing on it. >This is what we are doing : >> >> dump some data to lvm2 volume (using fio) >> take the snapshot >> delete the snapshot (no IOs anywhere after creating the snapshot) >> run the fio on lvm2 volume >> >> Here as you can see, we are just creating the snapshot and >immediately deleting it. There are no IOs to the main volume or >anywhere. When we run the fio after this (step 4) and we see around 50% >drop in performance with reference to the number we get in step 1. >> >> It is expected to see a performance drop if there is a snapshot >because of the COW. But here we deleted the snapshot, and it is not >referring to any data also. We should not see any performance drop >here. >> >> Could someone please help me understand this behavior. Why are we >seeing the performance drop in this case? It seems like we deleted the >snapshot but still it is not deleted, and we are paying the COW >penalty. >> >> System Info: >> >> OS : ubuntu 18.04 >> Kernel : 5.4.0 >> >> # lvm version >> LVM version: 2.02.176(2) (2017-11-03) >> Library version: 1.02.145 (2017-11-03) >> Driver version: 4.41.0 >> >> We also tried on latest ubuntu with newer version of LVM. We got the >same behavior. >> >> Any help/pointers would be appreciated. Thanks in advance. >> >> Regards, >> Pawan >> _______________________________________________ >> linux-lvm mailing list >> [email protected] >> https://listman.redhat.com/mailman/listinfo/linux-lvm >> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ > >_______________________________________________ >linux-lvm mailing list >[email protected] >https://listman.redhat.com/mailman/listinfo/linux-lvm >read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
_______________________________________________ linux-lvm mailing list [email protected] https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
