Solved

Hardware, Battery backed Cached RAID

Posted on 2012-04-11
3
492 Views
Last Modified: 2012-06-27
Is a battery backed RAID secure enough for Database work

How does recovery work, if the machine loses power, and only the battery is up and saving the cache, how does the machine recover when its powered up.
0
Comment
Question by:Los Angeles1
  • 2
3 Comments
 
LVL 15

Accepted Solution

by:
Perarduaadastra earned 500 total points
ID: 37833179
The battery maintains the contents of the RAID controller cache so that any delayed writes are preserved in the event of a power outage, and written to disk when the machines comes back up again. This avoids data corruption caused by the system thinking that data is present on the disk when it actually disappeared with the power...
0
 
LVL 15

Expert Comment

by:Perarduaadastra
ID: 37833249
Sorry, didn't answer the first question!

By secure, do you mean reliable? If so, RAID controller battery backup is another layer of data protection, though most servers, especially mission-critical ones, will have their own UPS protection against power loss and probably redundant PSUs as well. The battery backup of the RAID controller is most useful in scenarios where the wrong power cable is pulled by mistake in a densely populated rack during maintenance - easily done!
0
 
LVL 55

Expert Comment

by:andyalder
ID: 37833377
Most battery backed write cache lasts 72 hours, after that the battery goes flat and the cache is stale. For longer outages you may be able to have flash backed write cache, that has a small battery or maybe a supercapacitor to power it for the few seconds it takes to copy the RAM to a flash chip. It's possible that the cache will fail of course, or the controller itself could fail, not much you can do to cover that possibility.
0

Featured Post

Best Practices: Disaster Recovery Testing

Besides backup, any IT division should have a disaster recovery plan. You will find a few tips below relating to the development of such a plan and to what issues one should pay special attention in the course of backup planning.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Oracle Finace 3 77
ipconfig not working on windows 10 bash shell; what other commands are missing. 17 184
Linux hostname change 2 72
Shell Script on AIX 7 96
Patch Management is administrated by page 129 of  the following document:     http://support.dell.com/support/edocs/software/smdmc/11/en/ug/ug.pdf However, there are issues with Patch Management with FTP (for instance, a slow Internet connectio…
FreeBSD on EC2 FreeBSD (https://www.freebsd.org) is a robust Unix-like operating system that has been around for many years. FreeBSD is available on Amazon EC2 through Amazon Machine Images (AMIs) provided by FreeBSD developer and security office…
Learn several ways to interact with files and get file information from the bash shell. ls lists the contents of a directory: Using the -a flag displays hidden files: Using the -l flag formats the output in a long list: The file command gives us mor…
Learn how to navigate the file tree with the shell. Use pwd to print the current working directory: Use ls to list a directory's contents: Use cd to change to a new directory: Use wildcards instead of typing out long directory names: Use ../ to move…

810 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question