Bug 198676
Summary: | LVM operations and booting take a long time with large numbers of Physical Volumes. | ||
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Product: | Red Hat Enterprise Linux 4 | Reporter: | Ryan Powers <rpowers> |
Component: | lvm2 | Assignee: | Alasdair Kergon <agk> |
Status: | CLOSED NOTABUG | QA Contact: | |
Severity: | low | Docs Contact: | |
Priority: | low | ||
Version: | 4.0 | CC: | coughlan, kannan_hariharan, mbroz |
Target Milestone: | --- | ||
Target Release: | --- | ||
Hardware: | i386 | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2006-07-13 20:32:37 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: |
Description
Ryan Powers
2006-07-12 18:14:52 UTC
This seems like problem with too many copies of lvm metadata. You should probably use --metadatacopies 0 for most of PV's (and save only few backup copies and increase metadata area). See man vgcreate,pvcreate --metadatacopies remark (and also comment in 158687). I'm fairly certain I used --metadatacopies when originally creating the physical volumes. I did see the remark in the man pages. However, I have already pvremoved all the volumes, so I have no way to be sure if it was used or not. I will go back and test a few data points explicitly with --metadatacopies 0 and report findings. It turns out I misunderstood the notes in the man page. I just did a quick test using 10 copies of the metadata out of 1024 physical volumes and the run times of these tasks dropped to very acceptable levels. I'm marking this NOTABUG because it was user error. Hello Ryan, Couple of questions: 1. Where you using MPIO to manage the multiple paths? If so were the logical volumes created on the mpath devices or were you still using sd names? 2. Did you have any special definitions for the "filter" and "types" in /etc/lvm/lvm.conf? Regards, Hari (eLab EMC) The original configuration was using 256 x 4 with dm-multipath with volumes created on the mapped devices. During boot, I isolated the slowdown to LVM which is because of the misconfiguration and too many copies of volume group metadata. At the time, there was a filter setup to blacklist /dev/sd* from LVM (so that it would use the multipath maps), however, I don't recall defining any types. All the timing testing was done with 1024 unique LUNs. There was one path for each set of 256 LUNs. |