Disk cloning vs. Raid1

[DBissett]

I'm trying to arrive at the best possible solution for protecting a work computer from a HD failure, plus having an external backup of the drive. This is a little confusing and I can't decide if RAID1 or disk cloning is the best first step to take. From what I've read it sounds like these provide comparable solutions, except that RAID1 is automatic and continuous, whereas cloning is a manual operation. So is this the only difference between those two solutions. Either solution would provide an immediately useable backup HD if the first HD failed. Right? Then what would be best to put on the external HD? Clone to the external HD or send disk images to the external HD? The only difference here appears to be that the cloned "image" wouldn't have to be restored whereas an image backup would? Are there any differences in reliabilty, or large differences in speed or space requirements among these choices? Thanks. Any input appreciated.

 

[RebateMonger]

If you accidentally delete a file, get a malware attack, or get hit by lightning, your RAID 1 mirror will likely be worthless, too. The safest backup is one that's offline and located elsewhere. The purpose of RAID 1 is to keep your computer running if a single hard drive fails. It's not a backup.

 

[perdomot]

Raid 1 keeps your system working so that the office doesn't have to close up while you try to fix the mess because one of the hdds died. A clone of the array is good if something happens that damages both drives. There is no reason you can't do both things seeing as there are plenty of good cloning apps like Drive Image XML that are free. I use Norton Ghost and make two images, one on another hdd and one on DVD just to be safe.

 

[DBissett]

Thanks....Acronis TI allows you to clone the drive, and/or make drive image backups. Are these functionally the same thing? From what I've read I've gotten the idea that the only difference is that a drive clone is useable as is, where as the drive image backup must be restored to a hd to be useable.

 

[perdomot]

You usually clone a hard drive when you are going to replace the main drive with a newer/faster/bigger hdd. Once cloning is complete, you pull the old hdd and boot off of the new drive rigt away. With backup, you keep the backup image on a dvd or external hdd and restore that image if the main pc hdd suddenly dies. Raid 1 is the best for a business enviroment since it keeps things working but having a backup image in case both hdds die is prudent since you can go buy two new hdds and restore the image to the array. I'd set up the raid 1 array first and then create an image onto a couple of dvds/external hdd.

 

[RebateMonger]

Originally posted by: DBissett
Thanks....Acronis TI allows you to clone the drive, and/or make drive image backups. Are these functionally the same thing? From what I've read I've gotten the idea that the only difference is that a drive clone is useable as is, where as the drive image backup must be restored to a hd to be useable.

That's a pretty good description. The "problem" with a clone is that it's a copy at one moment in time. If you do images, you can usually keep records of changes in the state of the PC and can choose from a selection of restore points.

 

[taltamir]

protection should not be based on technology, but on things you want to protect against...

Make a list of possible disasters and then methods to protect against:
1. HDD failure: raid1 gives best protection since the other drive contains all the data at that exact moment, nothing is lost, and the system can keep on working while the drive is being replaced. Backups are secondary because new changes will be missing, so you will have to first fix the system, then redo all the latest work.
2. Theft: Only burning it on write once optical media (or off site backups) protect you, since it is worthless and will likely not be stolen along with the expensive electronics, it helps to hide it.
3. Lightening strike: Use a surge protector
4. Fire: Store a backup offsite or in a fireproof safe
5. Virus / Accidental deletion: NOD32 antivirus, and backup that is not attached to the computer (or can be shut off, like an external drive that you turn on, backup, then turn off).

for most people covering all those bases is unfeasable. I personally prefer RAID1 to a backup, since HDD is the most likely of those disasters, and backups are never as up to date as you would like them to be.

 

[geofelt]

The value of raid-1 for protecting data is that you can recover from a hard drive failure quickly.
It is for servers that can't afford any down time.
Recovery from a hard drive failure is just moments.
Fortunately hard drives do not fail often.
Raid-1 does not protect you from other types of losses such as viruses,
software errors, operator error, or fire...etc. If your motherboard fails, then your raid also fails.
For that, you need EXTERNAL backup. You will want to take an initial backup of your entire system. Then, implement a policy of taking incremental backups of data that is important to you.
If you have external backup, and can afford some recovery time, then you don't need raid-1.

 

[taltamir]

hard drives fails more often then a virus destroys data on a machine protected by NOD32 (which is never... www.eset.com), and way more offer then I "accidentally delete files".

Also, there is more then just downtime that is lost. If your backup is a week old, then you loose one whole week of work, downloads, files, etc... and it is hard to know WHAT exactly you lost so that you could recreate it.

software errors, operator error, or fire...etc. If your motherboard fails, then your raid also fails.

Backups are just as flammable. And RAID1 does NOT fail if the motherboard fails, only raid 0 and raid 5 fail if the mobo fails (and are recoverable, IF you wrote down the configuration data when you created them, and if you know what you are doing), or if bios is upgraded, or if you reset cmos due to OC, etc (which is why i say not to use them... single point of failure). The absolute worst case scenario for RAID1 is that it is no longer recognized as raid1, instead each drive is considered to be independent (yet each contain a perfect working copy of ALL your data, unharmed), so this "worst case" is not even remotely close to actually being bad... what you do in such a case is create a new array from a drive while choosing to preserve the data on the drive (all raid1 controllers, even mobo ones, allow that).

I DO agree about software errors. I create a cascading backup (different days backup to different folders) for specific things, like my firefox data (links) and quickbooks data, etc.. because those specific programs can ruin their own data (it happened to me before...)

For that, you need EXTERNAL backup.

The location does NOT matter, the PHYSICAL CONNECTION matters. the only way to make an external backup safter is to UNPLUG IT.
If the external backup is unplugged from the PC and from the power outlet then it is safe from lightening strikes. (although, a surge protector and the built in protection in a PSU might save it anyways). To protect from viruses the external backup must be unplugged / turned off / write once media (DVDR).

Raid1 - set up once, never loose any data from HDD failure.
Backup - create a backup every X time MANUALLY (if it is plugged in and online and automatic then it provides NO extra safety against viri or power surges). And when a hard drive fail, you loose X days worth of data.

Ultimate protection - RAID1 + Backups (ideally on cheap media in a fireproof safe off site).
Better protection - RAID1
Lower protection - Manual backup.
Almost no protection at all - automatic backup to external drive that is always plugged in and on.

 

[DBissett]

All of the suggestions/discussion have been helpful and I think I get the picture. I'll do RAID1 and have an eSATA drive I can backup images to, and unplug. As far as recovery time goes, in my experience I've been sidelined by an exploding PSU which fried everything in the computer, and a flood, which was a freak unexpected event. I appreciated the "events" list that somebody offered, which covered most everything except I felt like adding "acts of God". While I got back up and running within days (I did not have the redundancies in place we are talking about here), it took 1-2 months before I was able to reconstruct the entire environment I was used to, including all the programs, utilties, tweaks, and whatnot, both purchased and free. That makes a difference. I have not had a system go down in a few years but I do not want to get caught as bare assed as I was before. Thanks again. I will be prepared next time.