You have heard of the myth about water behaving differently from the northern hemisphere compared to the southern hemisphere. Especially when draining water out of a sink or bath. Well apparently this is a myth and not fact.
So what has this got to do with hard drives? Well the same was said about some of the old Maxtor hard drives and why they were built with clockwise disc rotation. Where they built for the southern hemisphere market and do they work as well in the northern hemisphere. Built in mid 2000 the Maxtor DiamondMax 10 hard drives were designed to spin in the opposite direction to the conventional mechanical hard drives.
I could not find any information as to why they were built this way and whether this design did improve performance depending on location in the world. Maybe this question will never be answered.
See pictures below of a the internal working of a conventional hard drive compared to the Maxtor DiamondMax 10 hard drives.
The other day I got an error message from Time Machine that it wanted to start from scratch with the backups on my Time Capsule. As I only use the Time Capsule as one part of my backup routine that was no big deal. I made sure my other non Time Capsule backups were up to date and then clicked Start New Backup. But what if the Time Capsule had been my only backup? I’d have been running without a backup for as long as Time Machine takes to backup my machine from scratch. Somehow I’ve trimmed my work laptop down to 78GB but it still estimated 6-14 hours until completion. (Yes, over wireless. No, I can’t relocate my office for the day.) What if my laptop died in that time? I’d have a dead laptop, a deleted Time Machine backup and an unfinished Time Machine Backup. In other words I’d be stuffed!
Now don’t get me wrong, I think that Time Machine has been brilliant in getting people making regular backups and I applaud the ease of use. The problem I have is that the language they use in their warnings is not strong enough. People should be more scared of losing their precious family photos or business files. There’s no need to sugar coat it. Also instead of deleting the old backup first, Time Machine should start a new backup and then delete the old one after the new one is verified. As long as there is enough free space of course. In my case there was plenty of free space.
I have included the original warning text below, along with my own version. I’ve not gone totally overboard, and sure it could use some work, but little details like this could really costs somebody some important data. It’s worth spending some time on.
Original Message Text
Transcript: Time Machine completed a verification of your backups on “Time Capsule”. To improve reliability, Time Machine must create a new backup for you.
Click Start New Backup to create a new backup. This will remove your existing backup history. This could take several hours.
Click Back Up Later to be reminded tomorrow. Time Machine won’t perform backups during this time.
Transcript: Time Machine has found a problem with your backups on “Time Capsule”. First backup any important files, then click Start New Backup. This will create a new backup and then delete the old one. This could take several hours and you will be at risk of data loss until it completes.
Click Back Up Later to be reminded tomorrow. Time Machine won’t perform backups during this time.
There are a few interesting things to point out here. As you are starting from scratch with the backup, you lose any old versions of files that Time Capsule had stored. It’s bad practice but some people will happily delete files from their computer, safe in the knowledge that Time Capsule has a copy. In that scenario, deleting the backup would be a disaster!
I still don’t know exactly what caused the problem with my Time Capsule backup, but since starting again I haven’t seen that message.
We often hear from people that have lost their data, despite having some sort of backup. It’s important to remember that your backup is no-longer a backup if it becomes the only copy of your data. We usually suggest having at least two forms of backup to cover this problem.
An example of a failed backup strategy came recently. A user had one server, and at the end of every day would duplicate the whole server to another server. This is OK for some scenarios and gives you a day-old server ready to bring out if your main server fails. We would have also suggested a second backup routine to run at the same time to some other storage. Preferably an external drive, accessible from a standard computer.
The system worked fine for over a year, until server 1 failed one day. Instead of replacing the disks and then restoring from the backup, it was decided to reuse the original disks and then load them from the backup. They overwrote server 1 with the backup from server 2.
When the restore was complete, it was discovered that the data on server 2 was actually corrupt. This corrupt data had also been written back to server 1. The client ended up with two corrupt servers, and no good copies of the data. Worst case scenario.
You will often hear that deleted data isn’t really deleted. This is kind of true, but only until you overwrite the data with something else. By writing server 2’s data over server 1, that effectively overwrote the original data, and left no possible avenues of recovery.
Another common problem we see is with external RAID cases like the Netgear ReadyNAS. These can be setup in a mirror mode which keeps the same data on both disks. Theoretically when one disk fails, the other can still be accessed. In reality the failed NAS will often end up in an unusable state where access to the data is not possible anyway. Even if you plug the hard drive directly into a PC, the NAS drives use a non-standard format so the data is not accessible.
The best way to avoid getting caught out by your backups is to never trust them. Be more paranoid. If you think you have a solid backup system then add another backup, just in case. Then next year add another. Most of the time it will seem irrelevant, but when your server and backup drives all get struck by lightning or end up flooded under six feet of water, you’ll be glad you spent the extra few pounds on an extra backup.
If you’re already using a Time Machine backup on your Mac then why not supplement that with a monthly whole-disk copy to a different drive. Carbon Copy Cloner or SuperDuper! can take care of it. This also has the advantage of being instantly bootable in an emergency and can even be stored in a locked safe, or at a friends’s house.
Like most external hard drives, Buffalo external drives are simply a wrapper around a regular hard drive. Aside from the protective shell they also have some electronic parts to convert between the internal hard drive and the external USB, Firewire, eSATA or Thunderbolt connections.
If you have problems with an external drive, you can perform a relatively simple test to check where the fault lies. Be aware that opening the external drive case will probably void your warranty, and if there is crucial data on the drive you should seek professional data recovery. That’s the obligatory warning out the way, so lets have a look at some troubleshooting.
First check all cables are plugged in securely, and not damaged or frayed near the ends.. If you have an identical drive with spare cables try them, but make sure you don’t plug in a power supply with different voltage! Hard drives don’t handle extra voltage well so you’ll end up in a worse position than you started.
If you know how, you could remove the hard drive from the external case and attach it directly to a PC to see if that allows access to the data. If it does, you should copy the data off straight away. The drive could still be faulty & fail again soon.
Whatever you do, don’t dismantle the actual hard drive. Hard drives are built in controlled clean-air environments and even the smallest spec of dust can cause permanent damage to the drive.
Since the introduction of unique ROM chips on the hard drives, it is often no longer possible to exchange circuit boards with another hard drive to access the data. In our experience circuit board problems are far less common than they used to be.
Now in a new 7mm slimline form factor, and Advanced Format specification, the HTS5450 hard drive is proving a popular choice for vendors with limited space. The drives are especially popular in Ultra thin laptops and slim portable external cases. Now being manufactured by Western Digital under the brand name of HGST, the 500GB boasts just a single media platter to store all that data. Part of the redesign also brings Advanced Format to these drives. Certain older operating systems such as Windows XP require the use of the HGST Align Tool provided by Western Digital. Users of the latest OS X systems and Windows 7+ do not require the use of this Tool.
Advanced Format has been introduced to cram more data on a single platter. To do this the manufacturer has increased the standard 512 byte sector size to a 4096 byte sector. This format design also incorporates better data integrity, hopefully giving the customer all round better performance and reliability.
A NAS (Network Attached Storage) puts storage onto your network, where it can be accessed by many computers. They often have more than one hard drive which can allow you to have automated copies of your data, which is known as RAID. A common type of RAID found on NAS devices is RAID 1, which will make two hard drives into a mirror copy of one another. Some manufacturers call RAID 1 Safe mode. If you have a NAS with two 1TB hard drives and set them to RAID 1 mirroring, instead of 2TB of storage (1TB x2) you only get 1TB. Everything you store to the NAS gets saved to both drives automatically. The theory is that if one of the drives fail, you can access all of the data from the other one. In practice that is not always the case. More on that later.
RAID 0 (Stripe)
Another common NAS option is RAID 0. The “R” in RAID stands for redundant, however there is no redundancy in RAID 0, so it’s not a real RAID type. If you setup the same two 1TB disks as RAID 0, you will get a 2TB volume to store your data on. The problem is that every single file you write to the NAS will be split into tiny pieces and distributed across both drives. If one drive fails, you not only lose the data from that failed drive, but also from the non-failed drive as it only contains half the pieces of each file. RAID 0 should never be used for long term storage, but can be fast so is often used for video editing.
So that’s the hardware taken care of. What other things should you look out for when choosing a NAS?
Another problem with most NAS devices is the non-standard filesystems they use to store the data on the disks. If the NAS itself fails, you cannot usually read the disks by attaching them to a standard PC. So even in RAID 1 mirror mode, you could end up with no usable copies of your data. Most NAS drives run a simplified version of Linux, but only some of them use standard Linux filesystems like ext2/3/4.
Backup my backup?
Some NAS drives have a USB port to allow you to backup the data to an external hard drive. This is great, as long as you can access the backup data on a regular PC, and it doesn’t need to go through the NAS. You can imagine why that would be a problem.
To summarise, NAS drives can be a great way to upgrade your home or small office storage. They can allow collaboration and sharing of files between users, and should simplify your backup process. Just remember that a NAS is a small server that needs to be backed up as a matter of urgency. As long as you have that covered then a NAS can be a smart addition to your network.
Plenty of shops will sell you a “Mac Hard Drive” but there is no reason why you cannot use a windows format drive on a Mac. You just need to format it first. There was once a time when a drive was specially formatted by Apple to use on their Macs, but these days Apple use the same hard drives as everyone else. To use with the latest versions of OS X I would recommend following the steps below.
NOTE: Formatting your drive will destroy all the data. Make sure there’s nothing on there you need.
1. First attach the drive to your Mac. The Mac will notify you with a small finder window to initialise the drive. See below.
2. Once you have clicked initialize you will see the Disk Utility Application window. See below.
3. You need to select the drive you want to format in the left hand window of the utility as highlighted in blue. Internal drives show as grey and external drives show as yellow. At this point make sure you choose the correct drive, the utility will not allow you to format the internal boot drive. See below.
4. Now choose the Partition Tab. See below.
5. Now click on the Partition Layout drop down bar and choose the first option “1 Partition”. Also to the right under Partition Information give your drive a name and below that choose the partition type you want which will be Mac OS Extended ( journaled ). We are nearly there. You now need to click on the options tab in the bottom left of the utility window and choose GUID Partition Table and click okay. As you will read in the text information, this allows the drive to be used with all current OS X Macs. See Below.
7. Now all you need to do is click the apply button as shown in red below.
8. Another window will appear asking for confirmation to partition the drive. Click partition. See below.
9. A formatting window with a progress bar will now appear and then disappear when done. You will now see your named drive in the left window, which means that your drive is now formatted. Close the disk utility and the hard drive is ready to use. See below.
SSDs (Solid State Drives) may one day become the standard form of storage in computers. Apple laptops are already heading that way. There are certainly many advantages when comparing SSDs to HDDs (Hard Disk Drives), however they do bring their own problems, which are often not well reported. We don’t care how good SSDs can be. We care about how they fail. It’s common to hear things like: “I’m replacing my hard drive with an SSD so I won’t have to worry about it crashing again.” While this is technically true – there are no moving parts to crash – there are plenty of other ways an SSD can fail. Whether it’s technically crashed or not doesn’t matter at all when you can’t access your files. It’s a shame but an SSD does not get you out of the boring task of running regular backups.
There are some pros and cons which specifically affect data recovery from SSDs. I haven’t listed things like battery life or read / write speed as they are not relevant when it comes to recovering data from them.
SSD Data Recovery Pros:
Shock resistance. No moving parts to crash.
Just as susceptible to filesystem issues, deletion, reformatting, bad sectors etc which can be recovered using existing equipment.
False sense of security. The word reliable comes up a lot in SSD marketing with phrases like “More reliable, faster, and more durable than traditional magnetic hard drives.” Maybe research exists that shows SSDs are less prone to failure but it doesn’t seem to be the case at the moment. Anything that holds your valuable data runs the risk of getting drenched, getting stolen, getting lost, and that’s before we even take general failures into account.
Susceptible to electronic failure, Maybe more so than a hard drive as the storage and electronics are combined in SSDs. Some of the most common hard drive failures are caused by errors in the firmware which controls the performance of the drive. SSDs have very complex firmware, which opens the possibility of firmware corruption. In most cases firmware corruption will block access to your data.
Encryption. Most modern SSDs encrypt the data at a hardware level, which makes it impossible to remove data chips and extract data from them externally (you can do it, but the data is encrypted). The keys to the encryption are often stored within the controller chip, so if that fails, you could be locked out of your data for good. Modern encryption works well. You can’t get round it.
Wear-levelling algorithms. Which move the data around the SSDs to improve performance, can make recovery difficult as these algorithms would need to be taken into account when accessing a failed SSD. They don’t store data in logical order like hard drives do.
We have been offering Apple Mac Data Migration as a service for many years now. Here’s a quick reminder about this service which we call Mac Setup. You are bound to be over the moon when you are told that we have recovered your lost data, but in many cases this is only half the battle.
We wrote a detailed blog on the subject back in November 2011, but it still appears to trouble many customers.
We still often get the questions: “What do I do with the recovered data once I receive it?” and “How do I get the data back into it’s original places on my Mac?” For out-of-warranty Macs, this is where our Mac Setup comes into play. For a fixed cost we will provide you with a new installed hard drive, with all your recovered data migrated into it’s original locations, so that when you receive your Macintosh computer back, hey presto! it’s as if your Mac had never failed in the first place, everything up and running as it was.
In most computers, when you save files they get stored on a hard drive. Although you wouldn’t know it, the drive does not store your files in a straightforward way. The data is written magnetically by a fixed comb of heads stacked above one another. These heads pass between several magnetic discs, writing data as they go. In most cases, instead of storing files on one whole disk they are split up and spread across the disks. This means that when we carry out data recovery we usually need all of the disc surfaces in good condition to get the data back.
When required we can use a process to take the data from the drive by one disc surface at a time. This can allow us to avoid a failing head until we have the rest of the data extracted. When we have extracted all of the data the parts are combined to allow access the files. In some cases this is the only way to get the data back.
Hard drives do not allow access to individual disks during normal operations so we need to use specialist hardware and software.
We commonly need to access individual heads on Hitachi drives, due to degraded magnetic discs. Also if a drive is dropped when in-use, it will often damage at least one head.