What QStar processes should be running in UNIX systems? 8
How do I know that set is mounted and healthy? 9
What is Covered error? 9
How do I know that something is wrong? 9
How do I perform mounted set cleanup? 9
How do I kill everything? 9
How do I know that data is communicated to Cleversafe ? 10
What files I need to send to QStar in case of error? 10
How do I perform data base backup? 10
How QStar Integral Volumes and CleverSafe Vaults relate?
The QStar Integral Volume (IV) presents a single file system which can be mounted, un-mounted or otherwise treated as a single namespace of the files with hierarchical structure. As mentioned before one IV is created on two CleverSafe Vaults – Metadata Vault and Data Vault.
The files and file metadata of such file system are created and maintained on the cache disk and subsequently migrated to the CleverSafe storage in the form of objects. The objects are of 4-16 MB size and may contain data from a single file or from multiple small files.
Can I use same vaults form different computers?
The data sharing shall be performed on the IV set basis. The IV set mounted on some computer can be shared through NFS or CIFS to other computers.
There is protection built in which allows to prevent CleverSafe vault pair sharing by some other IV on other computer. Technically this is possible to access vaults from any computer which can provide proper vault, user names and passwords. Unfortunately there is no tools to synchronize cache or vault modifications in consistent way. The protection processes attempts to mount the same vaults in the following way:
Can be mounted in read/write mode with “force” option.
“Clean cache”, Restore DB mount
The “Clean cache”, Restore DB mount allows to recreate status of the system (possibly modified by the Node 1) at some point in time. During clean cache, Restore DB mount (which is essentially is the method to recover state of the file system after computer crash) the QStar will restore data base from the CleverSafe Vaults, replay objects after data base backup and repopulate CFS data base.
Are QStar distributions compatible for different Linux versions?
You need to request from QStar distribution build for compatible version of the Linux.
RedHat builds usually are not compatible with Ubuntu, SuSe or other distributions. That is usually determined by libc and other libraries incompatibilities. 32 or 64 bit distribution flavors needs to be specified.
In which directory I should install QStar Software?
All UNIX distributions should be installed in directory /opt/QStar. Please note that Q and S are capital letters. The UNIX distribution images are linked explicitly for this directory.
Symbolic links are supported in all platforms except AIX.
How I extract QStar distribution?
The distribution is delivered in the form of zipped tar file. You need to extract the file into directory /opt/QStar.
mkdir –p /opt/QStar
tar xfz /tmp/linux_2.6_x86_64_v188.8.131.52xx.tar.gz
How I install QStar software?
The /opt/QStar/INSTALL script performs mandatory steps to install the software.
Confirm license agreement.
Select option 1.
Select option 5.
Select option 9 to exit.
How do I license QStar software?
You need to send to QStar host ID of your computer.
mountiv setname is the command to use. Here setname is IV set name. In this document the setname will be defined as “clever”.
There are following main options to use:
mountiv –n clever - mounts set and cleans cache. The data will be retrieved from the Cleversafe if requested.
Mountiv –Inf clever – recovers data base from Cleversafe and mounts with clean cache. There are several uses for this mount option. Testing is one. Clean everything is another. Moving IV set to other computer is third.
Should be used when moving system to other computer. May take some time. Better if backup was forced before moving.
How do I unmount IV set?
In some cases (when acesser is not responding to TCP/IP requests) “forced” unmount may be needed:
umountiv –f clever
How do I export QStar file system through NFS?
To export QStar file system (mounted as /mnt/clever) you need to create entry in /etc/exports file.
The standard Linux syntax of the /etc/exports apply but there is one mandatory parameter to be added: fsid=xxxxxx.
The fsid parameters value is not that important but every QStar file system (in fact every file system using FUSE driver) should have different value.
Please note that once you exported file system you will not be able to unmount QStar file system. It will return “busy” status until you un-export the file system from NFS.
To un-export file system:
export fs –u *:/mnt/clever
How I move QStar software to other computer?
To make moving smoothly the following actions needs to be performed on original installation:
Force migration of all Primary data to Cleversafe (using command mmarc –e –w clever or use GUI button “Start Migration”). If that is not done the Primary data residing in the cache will be lost. Obviously, if original installation is lost or damaged the data in Primary pages will be lost.
Perform backup of the data base. This is not essential step because data will be recovered , but having full data base backup will save recovery time since there will be no objects to replay.
emgcmd backup full clever
Unmount set on original computer.
If original computer just died you may expect some data loss if data was remaining on the cache.
If at this time some file systems were mounted you need to cleanup linux mount points.
After that QStar servers may be restarted using “/opt/QStar/install/rc start” and sets remounted.
How do I know that data is communicated to Cleversafe ?
mmparam clever will show changing numbers on lines:
Archived since mount:
Replicated since mount:
For especially curious following command sequence enables for 10 seconds and disables trace log:
emgcmd config log trace clever ; sleep 10 ; emgcmd config log none clever The log file will be in /opt/QStar/log/emg_debug_log file. Messages such as
Wrote [9099abe9dba9d3ec0687c4e4b182b7180000] 2138 bytes in 21254714 us
Indicates that writes are working.
clever: Object (MI102611V1:86f671a1c51e97de68feecc43a11e9a90000) was read, size is 4184488
Indicates successful reads.
Please note that trace log contains lot of other information not targeted for the end user. Prolonged run of the trace may slow down all operations. Nevertheless in some cases QStar service may request for such trace to analyze error situations.
What files I need to send to QStar in case of error?
In order to perform error analysis following information is required:
Content of the /opt/QStar/log directory.
Core files if any (/core* and /opt/QStar/cores/*)
How do I perform data base backup?
The data base backup is performed according to the file /opt/QStar/emg/files/clever_rc.xml.
If there is a need to perform data base backup on demand the following command should be used:
emgcmd backup full clever
The data base backup is initiated asynchronously and it is finished when syslog contains following line:
05/28/2012 13:00:32.811275 INFO clever: Full DB backup finished: size is 112256 bytes
Forced backup is recommended when IV set is moved to another computer or for any other good reasons.