What is a "Split Brain" Split Brain is often used to describe the scenario when two or more nodes in a cluster, lose connectivity with one another but then continue to operate independently of each other, including acquiring logical or physical resources, under the incorrect assumption that the other process(es) are no longer operational or using the said resources. In simple terms "Split brain" means that there are 2 or more distinct sets of nodes, or "cohorts", with no communication between … [Read more...] about Oracle RAC : understanding split brain
Archives for June 2015
How to mount the zfs rpool while booted from CD [SPARC]
To be able to troubleshoot booting issues, sometimes we have to boot the system in single user mode using the CDROM. This is required to access the root file system and find out the issue causing the boot problem. This post describes how to boot using CDROM and mount a zfs root file system (rpool). 1. Boot the system from a CDROM in single user mode. ok boot cdrom -s Boot device: /pci@8,700000/scsi@1/disk@6,0:f File and args: -s SunOS[TM] Release 5.10 Version Generic_137137-09 … [Read more...] about How to mount the zfs rpool while booted from CD [SPARC]
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 Use ‘zpool split’ to Split rpool in solaris 11 (x86/x64)
A mirrored ZFS storage pool can be quickly cloned as a backup pool by using the zpool split command. You can use this feature to split a mirrored root pool, but the pool that is split off is not bootable until you perform some additional steps. Some of the required actions are different for SPARC vs x86/x64 due to the difference of the OBP vs GRUB between the architectures. This article focuses on the steps required to split rpool in x86/x64 architecture. Caveats and Assumptions The … [Read more...] about How To Use ‘zpool split’ to Split rpool in solaris 11 (x86/x64)
How To Use ‘zpool split’ to Split rpool in solaris 11 (SPARC)
A mirrored ZFS storage pool can be quickly cloned as a backup pool by using the zpool split command. You can use this feature to split a mirrored root pool, but the pool that is split off is not bootable until you perform some additional steps. Caveats and Assumptions 1.The new/split pool must be used on the same host or the same server family type and architecture. ie: If the source rpool is imported and split on a T5120, the new pool must also be used on the same server type … [Read more...] about How To Use ‘zpool split’ to Split rpool in solaris 11 (SPARC)
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
How to add Additional Storage Space Created from Dynamic LUN Expansion in ZFS online
Most of the storage arrays nowadays provide 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 zpool as seen in the format command output … [Read more...] about How to add Additional Storage Space Created from Dynamic LUN Expansion in ZFS online
Beginners guide to oracle synonyms
Synonyms as the word literally means, are aliases for referencing the database objects. By default, when you look for an object in the database, it tries to search it in your own schema. So, if you are user user01 and you try to query an object emp from scott's schema, oracle will return an error : sql> select * from emp select * from emp * ERROR at line 1: ORA-00942: table or view does not exist Why do we need synonyms? 1. Synonyms make the referencing of objects … [Read more...] about Beginners guide to oracle synonyms