DevExpress Newsletter 8: Message from the CTO

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Honestly, no hardrive of my friends and relatives had broken in past ten years. Also could be considered that the PCs are usually replaced each 5-7 years, but still I see the chance as quite low ... Make backups anyway!

Something is a little off in your probability counts.

2x8 = 16 not 15.

and 8x8 = 64, which makes it 1 in 1.56 chance one of your old drives will die this year, not 1 in 2.  

So how do you backup? Seriously... We do our backups here to removable hard drive. I bet the failure rate on those is a lot higher since they can be moved even setting down on a table a little too hard might shake a drive head. Granted, we use multiple removable drives so if one fails we have options. Plus 2 of our servers backup to each other giving a 2nd restore option. Tape drives are definitely out of the question, especially for home use. The pricing and reliability of them (in my experiance) just makes them not worth it.

So what's the best option for home use when you have, say, over 20 gig worth of photos? I've been using DVDs, but even then people say that they degrade after a period of time.. It's not like I use these files daily, so I would need long term storage...

Please don't tell me you leave all your PCs on all the time even when not in use?

Dont give me that 'wears them out' bunkem - I've turned mine off every night and put them to sleep regularly with no issue - this is a computer not a 1970s Chevy.

Come on, get green!

In my experience, drives typically fail about 5 years into their service life or 90 seconds after their warranty expires. I always buy the 5-year warranty drives as the lifetime of the cheaper drives seems to be significantly shorter. Consider that replacement drives are often "remanufactured" and might not last out the last year of the warranty. Heat, use, vibration (induced into the cabinet by anything), high-G shock and more factors also shorten life. I speak from 35+ years in the business--lose the boot drive from your domain controller (as I have) only to discover that the Acronis backups are "corrupt" can wreck your month.

Nice article, Julian. I would just like to add to it the importance of auditing your backups. We have over 70 customers using the Mozy backup service. We monitor these backups for an additional service fee to our customers. Our monitoring has shown that on any given day, up to 10% of the backups are flawed in some way. Usually it is because the user has a dodgy internet connection. Sometimes, for unknown reasons, Mozy just stops sensing files that have changed and need backed up. In this latter case, the solution has always been to uninstall and reinstall the Mozy client.

My point is, no backup solution is perfect and you have to stay on top of yours and make sure that your backups contain what you expect.

Great post and spot on. To get the disclaimer out of the way, I'm the VP of Software Development at Intronis and we provide on-line backup services (and use Dev Express too, which is how I found this post). But since we have so many disks spinning at any given time, I can tell you that those percentages are accurate. Even we do not rely on one of our array configurations, but backup our backups redundantly and in two data centers on opposite coasts. Disks are mechanical items that fail. It's not a question of IF, it's a question of WHEN. And any service that fluffs the question of a backup of their backups isn't really taking these events seriously. So make sure you ask that question.

So when the disk fails, as it will eventually, you need a backup. And we all (me included) are bad about manual backups. So setting an online backup to keep you safe is by far the best option in all failure scenarios. Especially all you coders ...I can't imagine finding out the last backup of my code was a month ago! Keep your data safe out there.

Backup is the first thing you should think of, and the last thing you actually do. I use an external HD to backup my projects (when I think of it), and usually just ZIP up the files.

However, a few weeks ago, I synced with my new HTC phone, and it randomly trashed my contacts. Guess what... no backups. So I am now using iDrive to save it all.

Why is it we tell others the best things to do, and leave our own data to the last?

- Richard.

I suspect those failure rates are for drives in heavy use.  OUr company has 30 machines and they have all been replaced when they were at least 5 years old and the new machines are probably a year old now - there have been no HD failures.  However we have 3 servers and have had 2 drives fail in the past five years.  So, I don't really think those stats apply to PC's not used as servers.

The problem with backups is that data from one hard drive is typically backed up to another hard drive which can also fail. This happened to me recently at home when one of the hard drives on our NAS failed (4X250 Gig). Luckily, we run the NAS as a RAID configuration and thus did not lose any data. Until we are able to move to solid state "drives", I will always feel less than secure doing backups to hard drives.

Mark's last paragraph is very correct! I know people that thought that they had everything they needed to restore an application (like a SharePoint App) and they didn't, so the app could not be restored.

Or even that file that you needed so much, didn't make it on you backup!

So, please do as Mark said, make sure your backup contains what you expect, and if they do, try to restore them, as a test, to make sure they are alright.

My last complete local backup was done an hour ago; online backup some time earlier in the day. Why ? The contents on my HD is what drives my business so I can't afford to lose it.

Not that I am immune to data loss, about 3 months my laptop's HD died away after 3 years of use. That is when I noticed that I had some important data on it: I didn't think so; until then.

HD drive failure is one part of the picture. What about stolen PCs ? About 5 years somebody broke into my office, gone the PC, the flat screen (not cheap back then), the iPaq and the digital camera. Thanks god the external drive, containing a fresh backup, was not at the same place. Since then I am also talking to all my clients about the backup issue.

I usually I start like this: "What would happen to your business if one day you find out that your PC or laptop is just gone ?"

Good point to note, and yes I have turned quite a few aces in the last year with one partcular brand of hard-drive.

I am not sure google study covers Solid State Drives, what is the likelyhood of SSD's crushing.

Raid cards and extra hard drives are cheap as chips. I tend to run "App" and "Data" drives and make sure that all the software I need to rebuild the "App" drive is to hand on permanent media. If you cost up your time rebuilding than a RAID setup (even on a home PC) pays for itself in nothing flat.

As for being the tech gopher, try ringing a few friends at 9.30 p.m. now and again to ask for urgent help in their professional specialty. My buddy the spanish teacher eventually got the message after a lengthy discussion of castilian verb tenses late one night. (Don't try this with Health professionals - you'll find out things you never wanted to know....)

Can I just say this is the reason I *love* Windows Home Server?  I've been running one in my home with 5 drives for just over 2 years now (since the beta), and I've already gone through a seamless hard-drive failure, with no data loss.  WHS has to be far and above the best product MS has ever produced.

I use *HDTune* on my laptop to prevent the drive from overheating. I have lost an entire drive because of a motherboard fault that caused it to overheat. I literally burnt my fingers.

I use *Spinrite* every 3-4 months to check the status of each drive and test the surface. It has prevented several disasters.

Finally, I use a USB external drive for backups and archives. And I use *Acronis TrueImage* to make a complete disk image of my laptop, so if I'm struck by a virus or drive failure I can get my apps, registry settings and data back.

I've had too many close calls to NOT do backups, and with laptop theft a common occurrence, I can't afford to lose all my data.

I think the most sensible "should I back up?" metric is not the probability of loss, but rather the expected value of the loss.  All my work is checked into source control (elsewhere), so for me the expected loss is the last few hours' work, plus the cost of an OS and app reinstall, times two percent, which makes it acceptable to do no additional backups.  However, when I tell my mom that in the coming year, there is a 2% chance that she will irretrievably lose all of her precious photos, documents, and records, that same 2% number doesn't feel "low" to her at all.

I am too one of the lonely fighters for the necessity of complete, frequent and automated backups. Having that said, I want to pay your attention on the fact, that the given statistics may be incorrent. As the probability of one disk failing is independent of anothers disk failing, you must not multiply probabilities but adding them. So "The probability that at least one of those 8 dying this year according to Google's probability is 15%" must read "is 2%". But of course disk have kind of paradise at Google´s - nochanging temparature, climate control, ..., nothing we have at home.

Cheers Bernd

I dashed off a quick " Message from the CTO " about disk drives failure probabilities and backups for the eighth DevExpress newsletter , and, for such a quick message, it really resonated with the customers. It's always the way: it seems the