1. Revisión Bibliográfica
1.9 Fermentación de la bebida de soya con bacterias ácido lácticas
1.9.2 Microorganismos utilizados para fermentar bebida de soya
This chapter explains the procedure that you would use to recover your Compaq True-64 Unix operating system disk in case of a complete system failure-when you are left with nothing but bare metal. For suggestions on how to avoid this situation, please read the first section of Chapter 7, SunOS/Solaris.
Compaq True-64 Unix, also known as Digital Unix, is a Unix-compatible operating system based on the Mach kernel and is the main survivor of the Open Software Foundation. It is different in a number of ways from Solaris, AIX, and HP-UX. During OS installs or during backup and restores, one difference shows up quickly: there are two different filesystems supported by Compaq Unix. First, there is UFS (Unix File System), which is commonly found on many other Unix flavors. Second, there is Digital's proprietary filesystem known as the AdvFS (Advanced File System). AdvFS provides a journaled filesystem, cloning, volume management, and other advanced features.
I would advise against using AdvFS on the operating system partitions. There are a number of reasons, but the first is the most compelling: during a bare-metal recovery, simplicity is a virtue. Unless you're very comfortable with AdvFS, it isn't simple. The primary advantage of AdvFS is that you are dealing with large data volumes rather than the relatively small and static OS partitions. Also, until very recently AdvF still had a number of bugs that could jeopardize the stability of a system.
Another difference is that Digital has software upgradable firmware, similar to Sun's OpenBoot PROM, which supports, depending on the hardware, booting NT, Compaq Unix, or OpenVMS. During any operating system upgrade, make sure to upgrade the firmware also. This firmware, also known as the ''console," is like a minioperating system; it provides for configuration, diagnostics, and booting. During a bare-metal recovery, you need to be familiar with the firmware console.
Page 283
This chapter was written by Matthew Huff, director of operations at OTA Limited Partnership. Matthew has worked as a computer professional since 1987 and specializes in complex cross-platform system architecture. He can be reached at [email protected].
Compaq's btcreate Utility
Digital provides a system, similar to IBM'smksysb, which creates a bootable tape designed to shorten the time it takes to completely restore a system. The tape consists of a tape boot block, a specialized kernel, a stripped-down operating system, and a backup of your system partitions. Once it is created, complete restores are as simple as booting the prepared tape from the console:
>>> init >>> show dev
>>> boot -fl "nc" MKA400
You should create such a tape after a new system has been completely configured and after any major is made. Because the facility utilizes dump or vdump, the normal caveats apply. Ideally, you should create the tape while the system is in single-user mode. This, however, restricts the ability to automate the process.
The btcreate Command
The command to create the bootable tape is /usr/sys/bin/btcreate. If you run the command without any parameters, it prompts you for the missing information. First, it asks you for a kernel configuration file to use; make sure the kernel it creates will have the correct configuration for the devices that you need during a restore. Next, it asks whether to use a memory filesystem (ramdisk) to load the operating system during the restore. If you don't use the memory filesystem, you need to specify a partition to use (typically, the swap partition). Also, the command asks the device address of the tape drive you wish to use. Finally, it asks which partitions to dump and append to the bootable tape. Since once you have the OS completely restored, you can easily use your standard recovery tools, so it is best to specify only the OS partitions for the bootable tape.
If you don't want to use the interactive prompt, you need to specify at least the -f, -k, -m, -t, and -s flags: • The -f flag forces btcreate to overwrite an existing filesystem.
• The -k flag specifies the name of the kernel configuration file in /usr/sys/conf.
Page 284 • The -m flag allows you to specify a memory filesystem or a partition to use during the restore.
• The -t flag specifies the device to back up to.
• The -s flag allows you to specify a file that contains a list of filesystems to back up. Each line of the file must specify the device name, mount point, and type (UFS or AdvFS):
# /usr/sys/bin/btcreate -f -k ALAMO -m mfs -t nrmt1h -s /nfsdrive/btcreate.alamo Using the Bootable Tape
Once you boot from the tape, it loads the kernel and the miniversion of Compaq Unix. It then starts /sbin/btextract to begin the restore. It prompts whether to perform a default or advanced restore. Be careful: with a default restore you cannot choose which partitions to restore it restores every one that was specified in the file used for btcreate. The advanced restore prompts you for parameters including which partitions to restore.
Homegrown Bare-Metal Recovery
If you are in a heterogeneous environment with other, different Unix systems such as Sun, HP, or IBM, you might want to use a consistent method for bare-metal recovery among all your machines. This section shows how the homegrown recovery procedure described in the previous chapter can be applied, providing a complete custom bare-metal recovery plan for Compaq Unix. In addition, Digital provides a very powerful proprietary system for bare-metal recovery that has many advantages and is covered in the next section.
Before Disaster Strikes
1. If you are going to replace the root disk with another one without reinstalling the OS, you will have to partition the new disk the same way the old one was partitioned. The only way you are going to know that is to save this partitioning information. (It also would help if all your OS disks were partitioned in the same way.) You can use disklabel to print the current partition information:
# disklabel -r raw-disk-device
Page 285 2. Save the /etc/fstab file. (This file is very useful when trying to rebuild a system from scratch.)
3. If you are using AdvFS, save the /etc/fdmns directory structure: # tar cf /nfsdrive/fdmns.systemname.tar /etc/fdmns
4. Send this information to a centralized system, or more than one centralized system, so you can access it if any server becomes unavailable. One of the best ways to do this is via email.
The best way to do the first four steps is to use SysAudit* from cron and save this information in a file every day. This file can be printed to paper or copied to multiple locations for later reference.
5. Back up the OS. An easy way to accomplish this would be to use the program bostdump.sh. For example, suppose that the operating system is contained in the filesystems /, /usr, and /var. To back up these filesystems with hostdump.sh, enter the following command:
# hostdump.sh 0device logfile hostname:/ hostname:/usr hostname:/var
If you are backing up an AdvFS filesystem, be aware that vdump uses a small percentage of the partition to store information. If that filesystem is very near 100%, vdump might not be able to dump that partition, especially if you are using the -x option. (The -x option provides tape checksums, which, while slowing normal backups somewhat, are a very good feature and should be used.)
Step 5 creates a single tape that contains a full backup of /, /usr, and /var from hostname. Send this backup offsite for safekeeping, keeping an onsite copy for quick restores.
After Disaster
If you followed the preceding steps, you should be able to easily recover from the loss of an operating system drive:
1. Replace the root drive with a drive that is as big as, or bigger than, the original root drive. (Past experience has shown that the closer you stay to the same drive architecture, the better chance of success you will have.)
2. If your original disk was close to 100 percent utilized, you will need a larger partition than the original. 3. Determine the name of the console device.
* SysAudit and hostdump.sh are on the CD-ROM, and are available at http://www.backupcentral.com.
Page 286 In order to boot an alphastation or alphaserver from CD-ROM, you will need the name of the console device. The console of Digital's alphastations and
alphaservers has a different naming scheme than Compaq Unix. The main reasons for this is because you can run NT, Compaq Unix, or OpenVMS on the same hardware. Each operating system has, of course, its own dissimilar device names and structures.
Here is sample output from an alphastation:
>>>show device
BOOTDEV ADDR DEVTYPE NUMBYTES RM/FX WP DEVNAME REV
--- ---- --- --- --- -- ---
ESA0 08-00-2B-39-78-99 , TENBT
DKA300 A/3/0 DISK 1.05GB FX RZ26L 440C
MKA400 A/4/0 TAPE RM TZ87 971B
DKA600 A/6/0 RODISK 655.97MB RM WP RRD43 0064
... HostID
The device name, listed in the BOOTDEV column, is the label you use for booting, diagnostics, etc.; it is created from a combination of the device type and address. The first two characters are based on the device type (DEVTYPE column):
DK Individual SCSI disks, IDE devices masquerading as SCSI devices, or external RAID controllers DR Internal RAID controllers
MK Individual SCSI tapes JK Jukebox SCSI media changers DV Floppies
ES, EW Ethernet
PK SCSI controllers
The third character is based on the controller, i.e., A for the first controller, B for the second, and so on. The remaining digits indicate a sequence number. For SCSI, they are based on the SCSI ID and SCSI LUN. LUNs are used mainly for large drive arrays or media changers. Normal SCSI devices also have a LUN of 00. For example, DKA300 would be a SCSI disk on controller A with a SCSI ID of 3 and a LUN of 00.
Other console variables can be listed by the show command at the console or by using consvar -l under Compaq Unix. 4. Boot the system to the "Install Unix Shell" using the operating System install CD-ROM.
Page 287 >>> init
>>> show dev >>> boot DKA600
5. Select "Unix Shell" from either the text or graphical interface.
6. If the drive was partitioned with the default layout for that particular Digital drive type, use the -rw option of disklabel to partition the drive. The disklabel utility requires that you specify what type of filesystem the root partition is so that it can write the correct boot block on the disk:
# for UFS root partitions
# disklabel -rw -t ufs device digital_drive_type # for AdvFS root partitions
# disklabel -rw -t advfs device digital_drive_type
If you had a custom partition table, you will have to use vi to edit the partition table: #for UFS root partitions
# disklabel -rz -t ufs device digital_drive_type # for AdvFS root partitions
# disklabel -rz -t advfs device digital_drive_type # disklabel -re device
7. If you have a third-party drive, there is an undocumented trick to setting up the partition table, disklabel can be made to use the SCSI geometry command to scan the disk and set a default partition. Instead of specifying the Digital drive type, you use the device twice. This forces disklabel to read the SCSI geometry:
# for UFS root partitions
# disklabel -rz -t ufs device device # for AdvFS root partition
# disklabel -rz -t advfs device device # disklabel -re device
8. Create a new root filesystem on the disk: # for UFS partition
# newfs /dev/raw_device digital_drive_type # for UFS partition
# fsck /dev/raw_device # for AdvFS partition
# mkfdmn -t digital_drive_type /dev/raw_device root_domain # for AdvFS partition
# mkfset root_domain root 9. Create a mount point:
# mkdir /var/mnt
10. Restore the root OS backup to /var/mnt. If you are using something other than hostdump.sh, follow its procedure. If using hostdump.sh, follow this procedure. First you need to get the electronic label from the tape.
Page 288 a. Rewind the tape:
# mt -t /dev/rmt0h rewind
b. Use tar to extract the label from the tape:
# tar xvf /dev/nrmt0h #Remember to use the no-rewind device.
c. Read /tmp/BACKUP.LABEL to find out which file(s) on the volume contain(s) the filesystem(s) you need to restore.
d. Fast-forward to the first tape file that contains the root filesystem that you want to restore. For this example, the first dump file is the one we want, so it's the second file on the tape.
# Remember to use the no-rewind device. # mt -t /dev/nrmt0h fsf 1
e. Restore the root partition. 11. Mount the root partition:
# for UFS partition
# mount /dev/device /var/mnt # for AdvFS partition
# mount root_domain#root /var/mnt 12. cd to the filesystem you want to restore:
# cd /var/mnt
13. Use the appropriate command to restore that filesystem: # for backups that used dump
# restore -Yrf /dev/rmt0h # for backups that used vdump # vrestore -vxf /dev/rmt0h 14. Unmount restore root filesystem:
# unmount /var/mnt 15. Halt the system:
# sync; halt 16. Boot to single-user mode:
>>> init >>> show dev
>>> boot -fl "s" DKA300
Restore remaining filesystems. Since the definitions of the AdvFS domains and filesets are stored on the root partitions in /etc/fdmns, no more AdvFS configuration is necessary.
17. Prepare the /usr partition: # for UFS partition
# newfs /dev/raw_device digital_drive_type # for UFS partition
# fsck /dev/raw_device
Page 289 18. Rewind the tape:
# mt -t /dev/rmt0h rewind 19. Use tar to extract the label from the tape:
#Remember to use the no-rewind device. # tar xvf /dev/nrmt0h
20. Read /tmp/BACKUP.LABEL to find out which file(s) on the volume contain(s) the filesystem(s) you need to restore. 21. Fast-forward to the first tape file that contains the filesystem that you want to restore:
#Remember to use the no-rewind device. # mt -t /dev/nrmt0h fsf 2
22. Restore the /usr partition. 23. Mount the partition:
# for UFS partition # mount /usr # for UFS partition
# mount domain#fileset /usr 24. cd to the filesystem you want to restore:
# cd /usr
25. Use the appropriate command to restore that filesystem:
# restore -Yrf /dev/rmt0h # for backups that used dump # vrestore -vxf /dev/rmt0h # for backups that used vdump 26. Repeat steps 17-22 for /var if it is defined on another partition, rather than within /usr. 27. Reboot:
# shutdown --r now
Page 290
10
HP-UX
This chapter explains the procedure that you would use to recover your HP-UX operating system disk in case of a complete system failure-when you are left with nothing but bare metal. For suggestions on how to avoid this situation, please read the first section of Chapter 7, SunOS/Solaris.
Bare-metal recovery under HP-UX 10 can be performed using tools provided by Hewlett-Packard with the operating system. Three primary options are provided, each suited to a particular situation.
Ignite-UX, included on the Applications CD, provides a tool called make_recovery. make_recovery can be used to build a bootable image of the system on a tape. When disaster strikes, the system can be booted from the backup media and rebuilt in the state in which it was saved. A significant advantage of make_recovery is that it can be run on a live system, thus minimizing the downtime imposed by bare-metal recovery planning. However, Ignite-UX imposes significant disk requirements and must be installed locally on each system that will be saved to tape. Furthermore, make_recovery cannot be used to recover a system that has already failed in service.
copyutil, provided on the CD-ROM, can be used to build an image of a system on tape, block by block. In the event of a disk failure, copyutil can be used to salvage the readable areas of the disk, since it will skip bad blocks during the backup phase. The image then can be restored to a new disk and any missing or corrupted files copied from other machines or restored from other conventional backup mechanisms. The primary drawback of copyutil, which prevents it from being useful as a production bare-metal recovery tool, is that the system must be taken down into the offline diagnostic environment to be used.
Page 291 dump and restore are best suited to back up user data rather than entire systems and also may be used to back up data on live systems. Restoration of lost user data from a dump tape is reasonably straightforward. However, as shown later in this chapter, recovering a failed HP-UX system from dump tapes is a painful and complicated process, which requires significant planning and manual effort. See Chapter 3, Native Backup & Recovery Utilities, for more details on the use of dump and restore.
This chapter was written by Steve Ferguson of Collective Technologies. Steve has developed system administration skills in both heterogeneous and HP-UX environments and can be reached at [email protected].
HP's make_recovery Utility
HP provides a tool with Ignite-UX called make_recovery, which can be used to create a bootable system recovery tape for an HP-UX system. In the event of a system failure, this tape can be booted from and will automatically restore the operating system to the state it was in at the time of the backup. Creating a system recovery tape requires that the appropriate Ignite-UX product (Ignite-UX 10-20 for HP-UX 10.20) be installed on the target system. This section lists the requirements for a recovery tape, raises some issues to consider when creating a system recovery tape, and details the use of the Ignite-UX utility make_recovery and the use of the recovery tape to restore a system. The make_recovery utility is similar to an older shell script of the same name provided with BRAT, an unsupported tool for creating bootable archive tapes, developed and distributed independently by a Hewlett-Packard engineer. The use of the unsupported BRAT utility is now obviated by the inclusion of the supported make_recovery in Ignite-UX.
make_recovery Requirements
The make_recovery utility requires that a DDS or 8-mm tape drive be attached locally to the system for which a recovery tape is created. The boot LIF volume can be