Raid-1 or Raid-5 ? Hardware based or Software based ?

dan99t

n00b
Joined
Jan 19, 2012
Messages
16
Hi,
I am buying a new Dell T-7500 workstation.

After a Hard Disk crash once, I learned that I need an extra hard disk always ready in case one fails.

Dell is offering either software based Raid -1 OR Hardware based Raid-5 using PERC6/i SAS/SATA Hardware RAID Card with either 3 OR 4 Hard disks.

Specs of system are :

CPU : Intel Xeon E 5645 at 2.4 Ghz
8 GB ECC DDR3 1333 MHz RAM
500 GB SATA 7200 RPM HDDs with either Raid-1 or Raid-5
Windows - 7 Ultimate 64 bit

Currently I clone my HDD using Acronis True Image Home so that I always have an extra HDD ready but it is not in real time so I will still lose some data.

Even if I get a Raid system I still would like to continue cloning the HDD & keep them in remote locations.

My main goal is always having a cloned drive Ready. My concerns are as follows & need advice.

(1) I am not much of a technical person so if anything goes wrong like a Hard disk failure, how difficult would it be to replace the failed HDD & Rebuild the array ?

(2) Would I still be able to clone a HDD as I am currently doing using Acronis software ?

(3) Should I get Hardware based Raid or software based & whether Raid-1 OR Raid – 5 & how many HDDs should I get ( 3 or 4 ) if I get Raid-5 ?

(4) I frequently Fresh Install Windows-7 in Primary Partition & I have 6 partitions. I just format the Primary Partition & Install OS. It is very easy to do now. But will it still remain same with Raid-1 OR Raid-5 ?

Thank You.
 
1. Generally you stick the drive in and tell the raid card to rebuild using either the bios or software for the raid. At work I generally do this hot and do not even take the arrays down.

2. I am not sure what you want to clone. I mean if you have the raid you can not clone individual drives unless you clone every drive and do that offline and in that case it may be a daunting task forcing the raid to use the clone unless you switch all drives back to the clone.

3. If you are using windows and want raid 5, 6, 50 or 60. I recommend real hardware sas raid + battery unit. Not motherboard or software raid. If your raid card costs less than $400 at newegg without the probably $150 battery you most likely do not have a hardware raid card. With that said you can get some of these used on eBay for $100. For raid 5 I recommend 4 to 6 drives. If you need more drives than that use raid 6 from 6 to 12 drives and after that possibly raid 50 or 60.

4. Yes. It will be just as simple if you use HW raid or raid 1.


Now the lecture. Remember that raid is not a backup (does not matter the raid level). RAID is mainly for keeping 100% uptime in the event of drive failure or two if you use raid 6. So whatever raid you choose make sure you have some kind of backup plan depending on how valuable your data is.

To me it does not sound at all like you need raid. It looks like a backup plan is all you need perhaps using the windows builtin backup.
 
Last edited:
If you're worried about simple redundancy, just use the motherboard integrated RAID 1. You won't notice it. RAID 5 can cause some write overhead unless you have a good hardware RAID card.
 
I would go with software RAID 1. It's just as fast as hardware RAID 1 (except it uses a tiny bit more CPU power), and you won't be up a creek if your hardware controller dies.
 
I'd like to had: TEST IT!

I had a Raid 1 in my dell... one disk died on me. Never was able to rebuild it.

So After i changed the hard drive, I took a spare I had I testedit:
raid 1 with disk A+B, install os and one game... tested the game it works.
shutdown
remove disk B and insert Disk C
reboot
you should need to go in your raid setup to tell it to rebuild itself...
reboot
if it works fine (play your game a little) then
shut down,
install drive b (not as a raid) boot, in your OS format it...
shutdown,
remove drive A insert B (raid1 = B+C)
rebuild the raid... and test if your os/game works.
 
I just wanted to know one thing:
when you are saying software based raid, are you talking about using the raid option in windows OR using the Raid capability of your Mobo?

Because Raid Software to me is Windows (big NONO)
Hardware Raid is either on Mobo (good for normal users)
or dedicated hardware raid (an extension card with it's own RAM, and CPU) good for servers
 
Now the lecture. Remember that raid is not a backup (does not matter the raid level). RAID is mainly for keeping 100% uptime in the event of drive failure or two if you use raid 6. So whatever raid you choose make sure you have some kind of backup plan depending on how valuable your data is.

To me it does not sound at all like you need raid. It looks like a backup plan is all you need perhaps using the windows builtin backup.

We recently had a raid 6 failure at the office on a SAN that was supported. That means 3 drive failed before the rebuild thus dead in the water. They where changing the first one when the 2nd failed and before the first onw was rebuilt we lost the third...
Thank God for frequent backups!
 
Simple:

4 drives
set up a striped set(2 disks) and another set to mirror it.

Outcome:

capacity and speed of a raid 0 set
A mirrored set for the eventual failure in a set.

Every onboard controller worth having can do it.
 
i have a 6 drive software raid5 (md) in linux that flies. 300-500mb/s read/writes.
 
Last edited:
We recently had a raid 6 failure at the office on a SAN that was supported. That means 3 drive failed before the rebuild thus dead in the water. They where changing the first one when the 2nd failed and before the first onw was rebuilt we lost the third...
Thank God for frequent backups!

So three drives failed within only a few hours of each other? That's extremely rare.

I have had RAID controllers fail, hosing the array. I have also had power supplies fail and not provide consistent power to a few drives, which also hosed the array. There is no substitute for backups.

That being said, I now have a Linux MD RAID-6 array consisting of 6 500MB 7200 RPM drives and two hot spares. I have only had to replace one drive in the past two years. It was having electrical problems.

I would still recommend RAID-6 over other RAID levels because you can at least lose two drives in a six drive configuration.

http://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_6
 
for most home users, a simple backup solution works well. I haven't messed with windows backup yet, But i've always been partial to free tools like Macrium Reflect, where I can just set it to copy the drive image and toss it onto another drive... takes about 10 to 30 minutes (depending on computer ability, size of backup, etc) to fully recover from an easy restore disc...

This also comes in handy when building a PC for a family member who cannot seem to grasp that the purpose of the internet is NOT to download and install every possible thing the can find. When I build the machine, I install all necessary software and updates, do a quick disk cleaning of temp files and general garbage, then make an image onto a large-ish drive I use specifically for these backups... I keep that drive sitting on a shelf until someone else decides to download something stupid... I know, I should just restrict their permissions as users on their own PCs, but I keep having this impossible dream that ...eventually... they will learn...
 
Back
Top