- 论坛徽章:
- 0
|
ufsdump doesn\'t need to be done under single user mode even through it is recommended that way. If your system is quiet, you may perform an ufsdump at multi-user level. This is especially true if you have ufs logging turned on. However you need to do that at your own risk. Here is the reason why it is better to perform an unsdump at single user mode. In UFS (Unix file system), for each file or directory you create, the OS is going to allocate an inode for it. The inode keeps the property information of the file or directory such as permission, size, and ownership along with the pointers pointing to the data blocks that actually contain the data. When you do an ufsdump, it backs up the inodes first and then the data. So if you are ufsdumping on a busy file system, let\'s say the ufsdump just backed up all 100 inodes but haven\'t started backing up the 100 files yet, a user logged in and created another file. When the ufsdump program comes back to backup the files, there are now 101 files. That results on your tape 100 inodes but 101 files. When you restore it, you will get file system inconsistency. So the official way to perform a clean ufs backup is:\r\n\r\ngo to single user mode\r\nperform an fsck on your file system\r\nunmount the file system ( not necessary for / /usr or /var unless you want to boot from cdrom to do it)\r\nperform an ufsdump on the file system \r\nre-mount the file system\r\nYou need to do this for each file system\r\nback to multi-user level\r\n\r\nOne hint is that when you perform ufsdump of multiple file systems to the same tape, make sure you don\'t overwrite each other |
|