There are many circumstances where major changes are being made to the system, such as a patchset install or OS upgrade, when it would be nice to have the option to undo those changes and revert to a previous system state in case something goes wrong. With software volume management and a little preparation, it is possible to keep a temporary copy of the boot disk and roll back to it if needed. The boot disk needs to be mirrored. SVM root encapsulation and mirroring [SPARC] In the … [Read more...] about Solaris Volume Manager (SVM) : How to Use Mirrors to Roll Back System Changes
SVM
Solaris Volume Manager (SVM) : Understanding metadb Flags
The state database contains the configuration and status information of all volumes, hot spares and disk sets. To provide redundancy we create multiple copies of the state database called as state database replicas. Now in case of losing any state database replica SVM determines the valid state database replica by using majority consensus algorithm. According to the algorithm it is required to have atleast (half + 1) to be available at boot time to be able to consider any of them to be valid. … [Read more...] about Solaris Volume Manager (SVM) : Understanding metadb Flags
Solaris : How to run savecore manually while booted in single user from CDROM
For various reasons it may be necessary to gather a crash dump while booted from alternate media, for example if the system is not booting properly from the normal boot disk. This document outlines the steps required to accomplish this. In general, the steps required are: Boot from the alternate media Mount the root filesystem Determine the dump device Save the crashdump from the dump device Unmount the root (and other) filesystems 1. Boot from the Alternate Media To boot … [Read more...] about Solaris : How to run savecore manually while booted in single user from CDROM
SVM : How to set boot device at OBP for mirrored root disk
The Open Boot PROM(OBP) aliases in solaris SPARC environments are created to simplify the access to hardware devices using user friendly names. They can be used in place of the full OBP hardware path at the “ok” prompt. The post discusses the procedure to set the Open Boot Prom (OBP) environment for SPARC systems properly if system is mirrored with Solaris Volume Manager (SVM). The terms "primary" and "secondary" are often applied to SVM boot disks. In practice neither disk is primary. The … [Read more...] about SVM : How to set boot device at OBP for mirrored root disk
Solaris 10 patching with SVM : Traditional method (non-live upgrade)
Like many others, I am a big fan of live upgrade when it comes to upgrading/patching solaris. This post is for the system admins who still wants to use the traditional method of patching for whatever reason they want to. The setup The example system we will be using has SVM based mirrored root. Preparation 1. Check the health of all metadatabase replicas (metadbs) and SVM metadevices. # metastat # metastat -c # metadb -i 2. Check the current boot device. # prtconf -vp | grep … [Read more...] about Solaris 10 patching with SVM : Traditional method (non-live upgrade)
SVM : How to Use Metadevadm to Maintain Device Relocation Information After Disk Replacement
This article describes the method used to maintain device relocation information for Solaris Volume Manager (SVM). Device relocation information is based on device IDs, and care must be taken to ensure that it is updated when a disk is replaced. Device IDs are unique identifiers branded to all disk drives and LUNs (SCSI, fibre channel, SAS, etc.). Every time a disk is incorporated into SVM, this identifier is read and stored in the replica database. This allows SVM to access the disk by its … [Read more...] about SVM : How to Use Metadevadm to Maintain Device Relocation Information After Disk Replacement
How to add Additional Storage Space Created from Dynamic LUN Expansion in SVM online
Most of the storage arrays now-a-days provides the feature of dynamic LUN expansion. This feature allows you to grow your existing volume on the fly without affecting existing data or I/O. Dynamic LUN expansion increases the capacity of the physical storage. You must then make Solaris aware that the device has grown, and if a file system resides on the device, it must also be grown. Before LUN expansion 1. Here is the disk that was used to create the SVM mwtadevice as seen in the format … [Read more...] about How to add Additional Storage Space Created from Dynamic LUN Expansion in SVM online
SVM : How to un-encapsulate root disk (SPARC)
There may be times when you want to boot from the unencapsulated SVM root disk by detaching one submirror. The term unencapsulation refers to a method of taking disk out of SVM control while retaining its content. The reason to do this can be many - For patching or when the system is not bootable when under SVM (this offcourse can not be done in multi-user environment and requires you to boot the system in single user-mode. The procedure remains the same in that case too) The setup where we … [Read more...] about SVM : How to un-encapsulate root disk (SPARC)
SVM – How to create Soft Partitions
Why Soft Partitions ? An obvious question in everybody's mind - why the hell do we need the soft partitions. Well, the simple answer is - A limitation existed in that a disk can only have 8 partitions, thus limiting the number of metadevices to 8 per disk. This may have originally been an acceptable limitation, but as disk sizes increased, the restriction became unmanageable. This is where soft partitions come into play. Soft partitioning allows a disk to be subdivided into many partitions … [Read more...] about SVM – How to create Soft Partitions
The ultimate Solaris Volume Manager (SVM) interview questions
What are the configuration files used in SVM ? /etc/lvm/md.tab 1. The file is empty by default. The file is only used when metainit command is issued by the administrator. It is configured manually. 2. It can be populated by appending the output of # metastat -p. For example #metastat -p >> /etc/lvm/md.tab. 3. It can be used to recreate all the metadevices in one go. Best used in recovery of SVM configurations. For example # metainit -a (to create all metadevices mentioned in md.tab … [Read more...] about The ultimate Solaris Volume Manager (SVM) interview questions