204 tìm thấy rằng, uống một ảnh chụp đêm của khối lượng hợp lý có chứa thư mục nhà của người dùng và tự động lắp nó cho phép hầu hết người dùng để đáp ứng các yêu cầu khôi phục của mình bằng cách chỉ đơn giản là lấy các bản sao tập tin bị mất hoặc không chính xác sửa đổi ban đầu từ ảnh chụp. | 204 found that taking a nightly snapshot of the logical volume that contains the users home directories and automatically mounting it enables most users to satisfy their own restore requests by simply retrieving the original copies of lost or incorrectly modified files from the snapshot. This makes them happier and also lightens my workload. Not a bad combination This hack explains how to create a snapshot of an existing volume and mount it and provides some examples of how the snapshot preserves your original files when they are modified in the parent volume. . Kernel Support for Snapshots Snapshots of logical volumes are created and maintained with the help of the dm_snapshot filesystem driver. This is built as a loadable kernel module on most modern Linux distributions. If you cannot find this module or snapshots simply do not work on your system cd to your kernel source directory typically usr src linux and check your kernel configuration file to make sure this module is either built in or available as a kernel module as in the following example cd usr src linux grep i DM-SNAPSHOT .config CONFIG_SM_SNAPSHOT m In this case the dm-snapshot driver is available as a loadable kernel module. If the value of the CONFIG_DM_SNAPSHOT configuration variable is n this option is not available in your kernel. You will have to rebuild your kernel with this driver built in a value of y or as a loadable kernel module a value of m in order to take advantage of logical volume snapshots as discussed in this hack. Even if the dm_snapshot module is available on your system you may need to manually load it using the standard modprobe command as in the following example modprobe dm_snapshot . Creating a Snapshot This section explains how to create a snapshot of an existing filesystem. The filesystem that you are taking a snapshot of must reside on a logical volume as shown by the presence of the device mapper directory in the following example df -Ph test Filesystem Size .
