Package: lvm2 Version: 2.02.168-1 Severity: normal Dear Maintainer,
the --cachesettings swotch (to lvchange) apparently accepts space-separated key-value pairs (this is undocumented, but not the issue here). For example: # lvchange --cachesettings 'read_promote_adjustment=8' vg_cerebro/bp However, different cache policies accept different key-value pairs. For example, smq does not support any key-value pairs, therefore switching the cachepolicy to it fails: # lvchange --cachepolicy smq vg_cerebro/bp device-mapper: reload ioctl on (252:1) failed: Invalid argument Unfortunately, --cachesettings, while enbaling changes to cachesettings, does not allow clearing the key-value pairs: # lvchange --cachesettings '' vg_cerebro/bp Command failed with status code 5. # lvchange --cachepolicy smq --cachesettings '' vg_cerebro/bp Command failed with status code 5. The fix, IMHO, would be to allow one to clear cachesettings. -- System Information: Debian Release: 8.5 APT prefers stable APT policy: (990, 'stable'), (500, 'unstable'), (500, 'testing'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.4.41-040441-generic (SMP w/8 CPU cores) Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/bash Init: systemd (via /run/systemd/system) Versions of packages lvm2 depends on: ii dmeventd 2:1.02.90-2.2+deb8u1 ii dmsetup 2:1.02.137-1 ii init-system-helpers 1.22 ii libblkid1 2.25.2-6 ii libc6 2.24-8 ii libdevmapper-event1.02.1 2:1.02.90-2.2+deb8u1 ii libdevmapper1.02.1 2:1.02.137-1 ii liblvm2app2.2 2.02.168-1 ii libreadline5 5.2+dfsg-2 ii libudev1 230-7 ii lsb-base 4.1+Debian13+nmu1 lvm2 recommends no packages. Versions of packages lvm2 suggests: ii thin-provisioning-tools 0.3.2-1 -- Configuration Files: /etc/lvm/lvm.conf changed [not included] -- debconf information excluded