Why RAID Can Be Bad For Business

RAID is often touted as the silver bullet in data storage. Increased storage capacity, resistance from hardware failures and improved performance. While these are all valid upsides to a RAID setup, there are also a few downsides which need to be addressed.

1. Extra Storage.

RAID can allow for a huge pool of storage, but with that storage comes great responsibility. You should factor in at least enough capacity to backup the RAID data somewhere else. If you can only afford 8TB of storage then you should only use 4TB for data and the other 4TB to back it up; Preferably on another machine / standalone system.

2. Redundancy.

The first letter in RAID stands for redundancy. This means you can afford to lose a certain number of disks without losing access to your data.  This also means that if you have a disk failure you need to get it replaced immediately, otherwise you’re running without redundancy.

3. Downtime.

Nobody likes downtime. If your 16TB RAID array goes offline without a backup then you have a couple of options. One option is to attempt to get the RAID back online by replacing disks, rebuilding the array etc, but this is risky. If this is your only copy of the data then rebuilding / reformatting the RAID could corrupt the data beyond recovery. Don’t do this if you don’t have a backup to fall back on.

The second and preferable option is to get the RAID professionally recovered. When we receive a RAID, the first thing we do is make images of all disks. This allows us to work on the RAID without risk. Then we use a read-only process to extract the data onto another form of storage. This is where downtime comes in. Unless you go for an emergency process, you could have to make do without the data for a number of days.

So What’s The Way Forward?

It’s one word. Redundancy.

Whatever you do, make sure your data is replicated across as many types of storage as possible. In an ideal world you would have a duplicate system running alongside the live system, which can take over if anything goes wrong. Then have the data on another type of storage, which you can access from somewhere else. Imagine if the RAID controller failed, and you could only access the data from that one machine.

It doesn’t matter how many backups you have if they all require the same system to access them.

I’ve only just scratched the surface here, but you should always look to make extra copies of your data. It may seem redundant now, but when your server fails containing all your data, all your accounts, all your client details and your website, you’ll be glad you kept that extra copy.

Burning Linux ISO to USB Using a Mac

My main computer is an old MacBook Pro. I often download Linux ISOs to install on other computers. In recent Debian-esque releases this is actually really simple.

1. I find it quicker and easier to install from USB so first insert a USB pen / stick of some sort.

Note: This USB stick will be erased, so don’t use one with data that you need to keep!

2. Next we need to find out which number has been assigned to the USB stick. If you only have one disk in your Mac then the USB will usually be disk1, but always check first. (Note: Disks are numbered from zero, so your internal drive should be disk0) On your Mac open Disk Utility, which is located within Applications / Utilities. (See Image)

Disk Utility
Disk Utility

Select the USB stick from the lefthand window and then click the Info button which is on the toolbar. (See Image)

USB Info
USB Info

You will get a pop up window with loads of information about the device. We only need the Disk Identifier. Make a note of this for later.

Disk Identifier
Disk Identifier

3. To allow us to write data to the USB stick we need to unmount any volumes currently on there. (see image)

Unmount USB
Unmount USB

4. Now comes the actual writing. First locate the Terminal application, again within Applications / Utilities. (see image)

Mac Terminal
Mac Terminal

5. Remember to change the code to match your Disk Identifier from earlier. There are a few things to note about the following command.

  • sudo – allows you to run dangerous commands, so will require an administrator password
  • Instead of typing the location of the ISO file you can just drag the ISO onto the terminal when required.
  • “if” means input file (in this case the ISO file), “of” means output file (the USB stick)
  • When we found out the Disk Identifier, it was disk1. That will work in the command, but we use rdisk1 instead, which gives us raw access to the disk. This may not be necessary, but it works for me.

There is a lot of discussion about block sizes, but I find 4MB is reasonable for writing ISOs to USB. In Linux we often type bs=4M, however the Mac prefers it like bs=4096 instead. It’s the same thing, just expressed differently.

The command:

sudo dd if=[drag iso here] of=/dev/r[disk number] bs=4096; sync

Example:

sudo dd if=/Users/dan/Desktop/linux.iso of=/dev/rdisk1 bs=4096; sync

If you’ve got it right, you shouldn’t get any feedback until it finishes. Your USB stick may have a blinking LED whilst the data is being written. For reference the 200MB debian-netinst ISO took just over a minute to write.

Once complete you should get something like:

48896+0 records in
48896+0 records out
200278016 bytes transferred in 95.151719 secs (2104828 bytes/sec)

This means you’re finished. Now eject the USB and try to boot your PC with it. The Mac may complain that the disk is not readable but just ignore that and try it on a PC.

Debian Boot
Debian Boot

Accidentally Installed Windows On Top Of Mac OS X

We have just completed a complex data recovery, where a Mac system had been inadvertently overwritten with Windows. The Mac drive originally had over 500GB of data, so we expected to get most of it back, we just didn’t know how good the structure would be.

It helps to visualise the layout of the data on the disk. before it was overwritten, the data would have looked something like this:

Overwrite Mac With Windows

Although the fresh Windows system is much smaller than the original data, it prevents you from seeing any of that old Mac data.

Once we made copies of the drive, we were able to reconstruct the missing parts of the Mac data, and could see all the original files and folders, with their original structure.

Luckily nobody had tried to fix the problem with this drive. Often the fixes people attempt are worse to recover from than the original problems.

ST373454LC Unusual RAID drives

ST373454LC Unusual RAID Drive
ST373454LC Unusual RAID Drive

We have recently recovered a RAID 5 array which consisted of three of these ST373454LC SCSI hard drives. These are solid, weighty drives, which don’t give off a great deal of vibration, despite spinning at 15,000 rpm; 3 times faster than most laptop hard drives!

Upon opening one of the drives for cleanroom rework we discovered why these drives  spin so quietly. In the picture below you can see that although the drives are standard 3.5″ form factor, they actually have 2.5″ disk platters. These smaller disks create less drag, and therefore can spin faster without stability problems.

Inside a ST373454LC Hard Drive
Inside a ST373454LC Hard Drive

These drives are not alone in mixing up the form factors. The popular WD Raptor drives also use a similar design.

Downside?

Of course the biggest downside to using smaller disks is the lower storage capacity. Typically SCSI hard drives are much lower capacity than their SATA counterparts, so this trade-off is acceptable for the speed and reliability increases. The relatively low capacity is further mitigated when the drives are used in RAID arrays.

Extreme Close-Up: Toshiba Hard Drive [video]

This is a video of a functional Toshiba laptop drive. Using a macro lens, we are able to see what happens when you read or write data to or from a hard drive. You can also see how the hard drive parks the heads off the disks when the power is shut off. This is to protect the hard drive from shocks during transportation.

It’s my first one of these videos so you can see my reflection in a couple of places, when I lean over to send different commands to the drive.

Archiving Old Data

Data Recovery Software - Do Not Erase!
Data Recovery Software - Do Not Erase!

I recently read a brilliant article about the guy that wrote the original Prince of Persia game for the Apple II in the 80’s. He had long since lost the original source code, until an old box of floppy disks was uncovered in his father’s apartment.

Sensibly, he enlisted some experts to help with the data extraction, and after a day of collaboration was able to release the source code online.

This got me thinking. Although I am meticulous with my backups of current data, I still have boxes of old software on floppy disks, which are happily degrading as we speak. John even found an old 212.6MB hard drive with some vintage data recovery software on it. Now this stuff isn’t always useful, but occasionally a really old drive comes down to us, and it is only this old software that can do the job.

As a result, John and I have started a project to get all of our old data recovery software from floppy disks and hard drives, and back it up to our file server. The 212.6 MB hard drive in the picture had 128MB of old DOS recovery software, which would easily fit on my mobile phone. Who knows when we might need it, but we now have it available when the need arises.

PC World Data Recovery Know How Now Who?

We recently noticed our local PC World store has stopped advertising data recovery services. They used to offer a simple in-house recovery backed by a large international partnership to take care of the more difficult drives.

At some point, maybe around the time Know How replaced The Tech Guys for their support, things seem to have changed. Users are now left wondering where to go, and who to trust to recover their precious data.

This could be a blessing in disguise for users, as they can now choose any data recovery service, potentially saving some money.

Some tips for choosing a good data recovery lab:

  1. Give them a call and ask some questions. If you don’t like the answers then go with your instinct and try somewhere else. Data recovery takes care and attention to be carried out successfully, but don’t let somebody baffle you with jargon.
  2. Look out for additional costs. If you see adverts for £99 or less then be wary of costly hidden extras. Get all costs up-front. Note that you will probably need to add the cost of a new drive to the final bill, unless you supply one.
  3. The most you should pay without getting any data back is a small diagnosis fee. Unless you need urgent out of hours work, you shouldn’t pay hundreds without first seeing a file list, or being talked through the data by phone.
  4. Until the data has been recovered, then it is impossible to say that it can or can’t be done. Don’t rely on promises or estimates.

If you need data recovery then give us a call. We have services to suit home users and businesses, and have been in the industry for over ten years.

Bang Goes The Theory Data Recovery

Bang Goes The Theory – Series 6 Episode 3 – March 26th

Bang Goes The Theory Data Recovery

I love Bang Goes The Theory. I loved the alcohol powered motorbikes last week and find it a good doorway into ideas, which are presented in a fun and interesting way. I was extra excited when I started watching episode 3, and relised they would be featuring data recovery. A perfect opportunity to dispel some common myths, and dish out a bit of advice in the process.

Deletion

The data recovery guy Rob, made a good analogy when he described deleting data as ripping out a page from the table of contents. That is pretty much how it works, and really simple to understand.

Data Recovery Experts

Yes they are the world leaders. I’m not going to dispute that, but I’m also not going to name them. They don’t exactly need the extra publicity. It’s worth noting that any decent recovery firm would have reached the same results from the batch of damaged drives.

Getting Physical

I do have a couple of problems with the way some of the drives were “destroyed.”

  1. Sledgehammer. This would have been a good way to destroy a drive, but only if it had been removed from the PC first. Effectively the metal PC case acted like armour, thus protecting the drive from the brunt of the impact.
  2. Tractor. Same as above. If the drive was bare, and on solid ground, then maybe the tractor would have done more damage. Instead, the PC case protected it sufficiently and all the data was recoverable.
  3. Golf Swing. This was great in the example shown, but is a bit unreliable. If you only hit the edge, or if the disk didn’t have glass platters then it may have been recoverable. Maybe take it apart first, then you can see if it’s damaged.
  4. Tea Damaged USB Pen. This was a good one. Solid state storage should survive liquid damage, as long as it is powered off at the time. When dried out, there is a good chance of getting the data back. The worst thing you could do is plug in a wet drive, as this would cause an electrical short, and potentially damage the electronics of the device, and even the computer you plugged it into.
  5. Big Magnet. This was a good one, and surprisingly effective. Only problems are the fact that most people don’t have a giant magnet, and unless you test it afterwards, you wouldn’t know if it had worked.
  6. Toaster. This is an interesting one for me. Of course the toaster damaged the PCB (circuit board) of this hard drive. These drives were quite old, so that was no major problem. If however these were more modern drives the story could have been quite different. A lot of newer drives encrypt the data using keys stored on the PCB. If you melt that PCB, then you have a very difficult job on your hands.
  7. Torched. 100% successful. If you can see the drive destroyed, then that’s perfect.

Optical Discs

Liz later made some good points about the reliability of CD / DVD storage. I agree that although the quoted life spans of DVDs are enormous, in reality DVDs often only last for a couple of years. We have had discs in for recovery that have been stored in temperature-controlled server rooms that have still failed well short of their estimated lifespans.

Hard Disks

Hard disks can last for ages. We have some here that are well over 15 years old and still going strong. The problem is that they can fail without any warning. It is sound advice to backup one drive with another, and then another. This is the only surefire way to avoid being stung by a failed drive. Dallas made a good point of moving one of the backups off site, which is also a good idea.

Scrambling Software

I didn’t like the scrambling advice given near the end. There are problems with the way hard drives are designed, which can prevent the software from accessing bad sectors, and hidden parts of the disk. Although only small parts of the disk, you could leave enough data there to be targeted by fraudsters or whoever.

I advise a two pronged approach. First erase / scramble the data, then physically destroy the drive. This makes it far less likely that your data could end up in the wrong hands.

Summary

It is good to see this sort of thing on mainstream TV, and the advice given was a good starting point for most people. Despite my points above, it was basically a good show: Interesting and informative, with a decent amount of good info.

Many people have little or no knowledge of the way their data is stored, so any way to bring this to their attention is good in my books.

Bigger Hard Drives of the Future

The Register has today posted two articles about the ongoing battle to expand hard drive capacities.

First is an actual device for sale, a 2TB Western Digital portable drive. This drive has a fancy new case and USB3 connection. It contains backup software and also the option to encrypt the data with a password. I wonder if it encrypts the data by default like some of their previous portables. (A bad thing!)

Second is a futuristic announcement from Seagate about their new HAMR technology. This new tech uses a laser to heat part of the disk before magnetising it. This apparently allows for much higher densities, theoretically paving the way for 60TB hard drives. There doesn’t appear to be any products using this technology at the moment.

60TB drives will be fantastic for backups, but horrible to backup without a new, faster form of connection. These would take almost forever (exaggeration) to fill up by SATA.

This news helps prove that hard drives are far from dead. It will take a long time until SSDs can cope with such massive capacities, at a similar cost to these beasts.

Help! My PC Won’t Start

Here are some common troubleshooting tips to use if your PC won’t start. This will help determine if your hard drive is having problems, and therefore if you need data recovery.

There are two main types of hard drive failure: Hard drives that are still recognised in the BIOS and hard drives that are no longer recognised.

You may also like to read 5 DIY Data Recovery Tips

Hard drives that are still recognised

Some common error messages:

  • 1st / 2nd /3rd Master Hard Disk S.M.A.R.T. Status BAD, Backup and Replace
    Press F1 to Resume
  • WARNING: Immediate back-up your data and replace your hard disk drive. A failure may be imminent.
  • Windows logo, with a progress bar underneath that just keeps whizzing round and round.

These hard drives are partly functional. They are communicating back to the PC, but may not work well enough to boot up. It is important at this stage to asses the value of the data on the drive. If it is absolutely crucial then don’t mess around with it. Our success from this type of drive is very high. On the other hand, if the data is of little or no value then you could try getting the drive to boot again, but beware: anything that runs for hours on a failing drive could be destroying the data instead of repairing it. You could end up in the category below.

Hard drives that are no longer recognised

Some common error messages:

  • Error loading system disk
  • Reboot and select proper Boot device
    or Insert Boot Media in selected Boot device and press a key_
  • DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER

These drives are completely unable to communicate with the PC at all (or they are not connected properly – check the cables). In this case, you will not be able to run recovery software on the drives as the software won’t be able to identify the drive.

These drives require a proper diagnosis to find out the cause of failure. This could be anything from an electronic fault, firmware fault or physical damage to the internal parts.

We can recover data from all sorts of hard drive failures. If the data is important, don’t risk losing it. Get it straight to us.