Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

Dynamic Storage Solution

Posted on 2004-04-10
8
Medium Priority
?
213 Views
Last Modified: 2010-05-18
Hi,

Can someone tell me about a good way to create a storage solution with several disks? I want some redundancy like RAID5 so that if a disk fails, data isn't lost and if I have not enough space, it should be possible to add more disks.

If RAID5 is the best way to go, can someone show me the way to a good dummy level tutorial (manual)?

Thanks in advance.
Greetz
Filips
0
Comment
Question by:Filips
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 3
  • 2
8 Comments
 
LVL 6

Author Comment

by:Filips
ID: 10796640
BTW: Working on Redhat ES v3
0
 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 10796657
I would suggest that you run LVM on top of a RAID 5 system. This way you have the advantages of a RAID system, butyou can also add more space if you need it: http://www.aplawrence.com/Linux/lvm.html
0
 
LVL 44

Expert Comment

by:Karl Heinz Kremer
ID: 10796662
BTW: LVM is the Linux Volume Manager, this HOWTO explains pretty much everything about it: http://www.tldp.org/HOWTO/LVM-HOWTO/
0
Efficient way to get backups off site to Azure

This user guide provides instructions on how to deploy and configure both a StoneFly Scale Out NAS Enterprise Cloud Drive virtual machine and Veeam Cloud Connect in the Microsoft Azure Cloud.

 
LVL 6

Author Comment

by:Filips
ID: 10797026
Question: will the to the LVM added disks covered by the RAID5. That is; when I have disk sda, sdb, sdc, sdd and sde in a raid 5 and I add a disk sdf to LVM and afterwards sdf fails and I replace the disk, will the data still be there?

Do I have to use RAID or is LVM alone enough?

Thanks in advance.
Greetz
Filips
0
 
LVL 9

Expert Comment

by:Alf666
ID: 10801410
LVM and RAID a *pretty much* the same things. At least, the same concepts.

RAID stands for Redundant Array of Independent Disks. There are different levels of RAID.

Basically :
- RAID1 is mirroring. This means that you have to use twice the disk space.
- RAID5 is the luxury RAID as it's the level for which parity bits are scattered across all disks. Its a bit expensive in terms of IO (slows the disk access down), but it allows you to "burn" any ONE of the disks, replace it, and rebuild without any data loss.

For more infos, have a look here :

http://www.raidweb.com/whatis.html

Hardware RAID implementations sometimes also allow "hot-swapping". This means that you can take off a disk even if the array is powered up. Thus replacing a disk without stopping the system.

LVM is just a (free) software implementation of different RAIDs. It's slower than a hardware implementation, but implemented in Linux at the kernel level.

So, it's your choice of which RAID you want to implement with LVM. The above suggestion of RAID5 by khkremer is good. You basically spare 1/5 of your disk space, but it's worth it if you need it.

So, to answer your question, all the disks you add to the RAID config will participate in your RAID array. And if ANY one of them fails (one at a time !), you should be able to replace it without any data loss.
0
 
LVL 44

Accepted Solution

by:
Karl Heinz Kremer earned 1500 total points
ID: 10801492
LVM and RAID are two completely different things. Some of the use cases to overlap, but in general we are talking about two different things. LVM allows you to combine different physical disks into a logical volume, you can add new disks when you run out of space, or take disks out of your volume group if you don't need it anymore. LVM does not provide any redundant data storage, which RAID does. With RAID your primary objective is to fault tolerant  data storage. You can run LVM on top of a RAID system (see my first link) if you need fault tolerant storage plus easy volume management.
0
 
LVL 9

Expert Comment

by:Alf666
ID: 10801547
Hem... Please ignore my whole comment. I mixed up lvm with md :-(

I'm going back to bed. Flu and computers don't mix so well...
0
 
LVL 6

Author Comment

by:Filips
ID: 10802846
Alf666, get better soon. I need you here.
0

Featured Post

Moving data to the cloud? Find out if you’re ready

Before moving to the cloud, it is important to carefully define your db needs, plan for the migration & understand prod. environment. This wp explains how to define what you need from a cloud provider, plan for the migration & what putting a cloud solution into practice entails.

Question has a verified solution.

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

How many times have you wanted to quickly do the same thing to a list but found yourself typing it again and again? I first figured out a small time saver with the up arrow to recall the last command but that can only get you so far if you have a bi…
SSH (Secure Shell) - Tips and Tricks As you all know SSH(Secure Shell) is a network protocol, which we use to access/transfer files securely between two networked devices. SSH was actually designed as a replacement for insecure protocols that sen…
Learn how to find files with the shell using the find and locate commands. Use locate to find a needle in a haystack.: With locate, check if the file still exists.: Use find to get the actual location of the file.:
This demo shows you how to set up the containerized NetScaler CPX with NetScaler Management and Analytics System in a non-routable Mesos/Marathon environment for use with Micro-Services applications.
Suggested Courses

688 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