I should have backed up sooner

[Emre Safak]

Originally Posted by Harm Millaard

I never heard this argument before and it makes me wonder why large corporations, or even small ones rely on for instance HP EVA configurations for their storage. If you can give me some solid examples you may convince me, but my initial reaction is that this is complete BS. I find it hard to believe that with storage capacities of up to 120 TB per 8100 system, you need to check files regularly.

Having heard without proof is IMO hearsay, always to be doubted and taken with a lot of grains of salt.

Here is a case:

...these pictures were stored on a primary hard drive and backed up to a mirrored RAID array. Unfortunately, when primary hard drive crashed I found that the RAID had been silently corrupting files for a year - but of course, without having a digest or checksum of each file and comparing them regularly, this could not be detected. I also had some CDs that went bad.

[Harm Millaard]

Your case does not prove your point. The post you quoted also said he had CD's go bad on him. This points more to where a large majority of errors occur, between the chair and the keyboard.

It does not mention hardware or software raid, nor the raid configuration, apart from mirroring, so it could be raid1, raid10, raid0+1.

There is no indication that a raid is to blame if he managed CD's to go bad. More likely is operator error or corrupted data on the primary disk from the start before the final failure.

[Emre Safak]

Not true at all. CDs go bad whatever you do. It is unrelated to the RAID issue.

[Thomas Edward Bufkin]

Well here's the skinny,

After repeated room temperature tries with no recognition I left it in a cold room overnight. Tried it the next day with the HD at 45 deg F. All the files and folders appeard on the drive.

I copied everything onto the new drive. It shows to be identical file sizes etc. But everything is corrupted.

I tried Ghost and the files were the same. So I checked everything from the new drive in Vegas and Windows Media Player. No help. Then I tried the same from the bad drive; same result. I was surprised the drive would still read after several hours of goofing with it.

So I rebooted and tried again. Same thing.

I disconnected every drive except C and the bad one E, no change. I relocated E to other SATA ports on the MOBO and it still came out the same.

At this point I thought I was scr***d. I decided to give up on the drive and data and reformat the drive a play with it with archived data. Then I discovered the most important of my files were copied on to My Documents in C.... WOW! Who did that? I don't remember doing that but WTF, lucky me.

So I've backed up the precious files, reformatted the drive in question, and I will see how it acts just for the experience.

About that freezing thing. That sounded kinda scary which is why I tried the cold room first. Maybe I should have cooled it down even more.

Here in Houston, Texas the weather changes rapidly from hot/warm humid today and cold dry the next.

My computer is inside a well insulated building but I do not leave the AC on all the time. Sometimes a few days pass before I turn on the Computer. There is probably as much as 30 degrees variation in temperature inside the office and humidity in Houston varies from a normal high of 80-85% to less frequent lows of 40-50%. Probably a factor.

I'll stop boring you guys,

thanks everyone for your input and three cheers for the knowlege base here at DV Info Net


Thomas Edward Bufkin

[Don Blish]

I ran a 24/7 database suite and thanked my lucky stars many times for RAID5 or mirroring to get thru surges and other short term disasters. However, for longer term protection and especially self inflicted "disasters", you need a SIMPLE backup medium, one that is NOT on line all the time. Thru 1999, that was always tape. Here we copied the live dataset to a new tape or to one that was, say, 10 generations old and rotated them. One went home with the sysadmin, the other 9 were in the safe. We ALWAYS bought tape drives in pairs: If the live machine melts, you will need a drive and software like the original.

Translating that to a world where discs are so cheap. I am determined to keep "My Archive Video" of .m2t and .iso files on my "C" array. Every 2 to 4 years I'll build a new machine with another 4 disc RAID5, I edit to a work volume on another pair (ie #5&6) striped RAID0. I then only use my eSATA external to put new projects on. As such it only runs once or twice a month. Occasionally I plug that eSATA drive into my Blu-Ray notebook and pull .m2t or .iso off it to check all is OK.

Edit: in summary, if it is your only copy, its not a backup!