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How to improve performance with LVM cache features?
To use LVM cache features to improve the performance of a Ceph cluster, you need to have: A running Ceph cluster in a stable state (‘HEALTH_OK’). OSDs deployed with BlueStore and LVM. This is the default if the OSDs were deployed using SUSE Enterprise Storage 6 or later. Empty disks or partitions that will be used for caching.
How to remove LVM cache from an OSD?
To remove existing LVM cache from an OSD, use the following command: If the caching device fails, all OSDs behind the caching device need to be removed from the cluster (see Section 2.7, “Removing an OSD” ), purged, and redeployed. If the OSD drive fails, the OSD’s LV as well as its cache’s LV will be active but not functioning.
Is the cache still available on the origin LVM?
The cache LVs still exist and cache info still shows them as being available. You will not be able to uncache because LVM will fail to flush the cache as the origin LV’s device is gone. The situation now is that the origin LV exists, but its backing device does not.
Is it safe to use data = journal in ext4?
– Unix & Linux Stack Exchange Is data=journal safer for Ext4 as opposed to data=ordered? The default journal mode for Ext4 is data=ordered, which, per the documentation, means that “All data are forced directly out to the main file system prior to its metadata being committed to the journal.”
How to use LVM cache for Gluster storage?
LVM Cache for Red Hat Gluster Storage 1 19.8.1. About LVM Cache. An LVM Cache logical volume (LV) can be used to improve the performance of a block device by attaching to it a smaller and much faster 2 19.8.2. Choosing the Size and Speed of Your Cache Devices. 3 19.8.3. Configuring LVM Cache. 4 19.8.4. Managing LVM Cache.
What is the difference between cachepool and cachevol?
There are two kinds of methods of how the cache is used: cachepool and cache volumes (cachevol). The main difference is that cachepool is using two logical volumes to store the actual cache and the cache metadata, where cachevol is using one device for both.
How to use LVM and dm-crypt to trim files?
TRIM a filesystem directly on /dev/sdaX and make sure that works (its quite possible that the device lies, and trim doesn’t read back zeros). Then dm-crypt on top of that, and trim a filesystem on that, and make sure it works. Finally, put LVM on top, and check that works.