2 questions

sybaris · 20 Mar 2011 at 22:40

Im looking for a new hard drive or drives and need some advice.

My current 1.5Tb is running low on space and is getting on a bit. I think its life expectancy is not too long either.

The questions are
Should I get a 3Tb drive or 2 2TB drives?

2 drives = better redundancy
1 drive = cooler and less power consumption, and well is only one drive.

The drive will be accessed by a single pc and not shared, though it is used for all round use.

Im not interested in raiding them.
I have an SSD for my OS (win 7 64 bit)

I've an ASUS P5Q-E mobo and I don't think it runs SATA 3.
As I understand something like the WD or the Hitachi 72000 rpm would drop down and use half the cahce. Is this true?

I also have a removable drive bay to backup on to other spare drives.

So what do you think would be best?

Surveyor · 20 Mar 2011 at 23:43

As you wrote the book on backups for an FTSE100 company you should be able to answer your own questions.

Also make sure you don't buy any of those dodgy drives. You know, the ones which are two drives stuck together

And I see you know as much about how a drive's cache works as anything else. A drive will use all of its cache no matter what speed SATA port you connect it to.

Using SATA2 ports will make no difference with a mechanical drive. SATA2 has around 300 MB/s of throughput which is far in excess of the speed of any mechanical drive except the new 72000rpm drives you refer to.

Personally I'd get two 2TB drives. A third extra storage for the same or less money.

Sorry, couldn't resist having another dig

cmndr_andi · 20 Mar 2011 at 23:59

Hi there,

If you are talking about redundancy and multiple hard disks then you really need to start talking about RAID. You could buy two 2TB hard drives and run them independently - but the chance of one dying and loosing half of your data is just as high as the single 3TB drive dying and loosing all your data. Obviously, one 2TB drive dying (out of two) is better - but you would still be loosing a great deal of data.

Personally, I would buy three Samsung F2 1.5TB drives for ~£50 each and run them in RAID5. This will mean you have spent £150 on 3TB of data storage and if one of the drives dies you don't loose any data.

As for running SATA 3 drives on SATA 2 ports - don't worry. Modern 7200rpm mechanical hard drives can only use around half of SATA 2 bandwidth at full whack.

Surveyor · 21 Mar 2011 at 00:07

The OP knows all about backups. Didn't you know they wrote the book on backups for an FTSE100 company?

They've said they're not interested in RAID.

In a previous thread they stated "In fact I mirror critical data, and I run regular full backups. Not your differential or incremental too. Just to be on the safe side I keep off site backups also".

Don't try and teach your grandma to suck eggs :rolleyes:

sybaris · 21 Mar 2011 at 00:57

Surveyor said:
As you wrote the book on backups for an FTSE100 company you should be able to answer your own questions.

Im sure in your haste to try to have a dig you noted where I said back in the day. To most people that would indicate it has been some time and that times have changed and I have move on to do more meaningful things. Hence, why I am a little rusty. Different times, different technology.

You are probably fresh out of tech school and probably don't even know what a LTO, dat4 or SDLT is. Back then before we had TB drives, there was tape and some long command line instructions. That was a real system. None of todays GUI point and click the schedule. Techies today have it so easy in comparison.

Surveyor · 21 Mar 2011 at 01:13

sybaris said:
Im sure in your haste to try to have a dig you noted where I said back in the day. To most people that would indicate it has been some time and that times have changed and I have move on to do more meaningful things. Hence, why I am a little rusty. Different times, different technology.

You are probably fresh out of tech school and probably don't even know what a LTO, dat4 or SDLT is. Back then before we had TB drives, there was tape and some long command line instructions. That was a real system. None of todays GUI point and click the schedule. Techies today have it so easy in comparison.

I gathered from your posts that you're a bit behind the times but when you make statements like "I wrote the book on backups for an FTSE100 company" you're asking for a bit of gentle ribbing.

And yes you're right. I'm fresh out of Tech. School, at the grand young age of 44!

Actually I just try to keep up on PC hardware as I've built several PC's for myself, family and friends. Generally I build new for myself and pass on older kit. The amazing thing is that you give someone a PC and they seem to think it comes with a lifetime parts and labour warranty. I seem to be responsible for looking after 9 PC's (7 of which I built and 2 I upgraded) and 2 laptops. Many's the happy evening I spend fixing someone's PC.

Usually I don't have any problems but we all have our moments

MagicBoy · 21 Mar 2011 at 01:16

I'd go with andi's suggestion above.

2 separate drives isn't better redundancy - there's more likelihood of one of them failing and taking some of your data with it. The way to mitigate this is using RAID 1 or 5.

JonJ678 · 21 Mar 2011 at 01:46

@OP, could you clarify what you're trying to achieve?

If it's to store 2tb of data, twice over such that one of them acts as a backup, it needs to be two seperate drives. If the data is backed up elsewhere, then a single 3tb one makes more sense.

I believe £/gb is on the side of two 2tb drives assuming you can make use of 4tb of storage. Power consumption is negligible.

sybaris · 21 Mar 2011 at 08:17

Hey Surveyor, no problem, was 1am when I replied and a little tired. Actually its nice to have a little banter on here. No offence taken.

This is for my home PC. I am basically out of space and replacing one drive in the system for another larger one.

Then I noticed that I could get 2x2TB drives for the price of 1x3GB drive. This put me in the dilema of one drive is easier, has less effect with airflow in my case, marginally less to power, though I have 3 drives in the case so far.

Im not too bothered with redundancy and backup, as one of the other existing drives has software mirroring and I have a removable drive bay for backing up.

I know this is not the most accurate method of calculating free space, but I normally estimate that i will lose 10% usable space on the drive anyway so 2 drives with 3.6gb each or 1 drive with 3.7gb. Not much in it.

Also I take the point.
1 drive is a single point of failure.
however 2 drives could mean twice the risk of failure or they could mean 1/2 the risk of failure. But as I mentioned that is not really a huge factor.

Are the Hitachi drives any good?

I think it comes down to
cost
hassle factor
access time (though for one standalone PC its not going to be too bad even at 54000 rpm)

JonJ678 · 21 Mar 2011 at 16:27

Um, gigabytes are different to terabytes, and 3 is different to 4. Quite a lot of typos there.

Two 2tb drives will provide approx 0.93*2048*2 = 3,800 gigabytes of space.
One 3tb drive will provide approx 0.93*3072 = 2850 gigabytes.

Hitachi drives are not good (in my experience at least). Stick to Western Digital for the safe bet, or Samsung if you dislike WD for whatever reason.

I think I'd go for a single 3tb drive if cost is too much of a concern. Splitting data across two drives is a pain, and going from 1.5tb to 2tb just doesn't seem worth the money. Otherwise I believe I'd have a dig through the contents of the current drive and delete a load of files (they're backed up anyway), and wait for 3tb drives to come down in price.