Advanced Format Drives
Standard drive blocks are currently 512 bytes long but, as you have heard so much recently, the drive manufacturers are moving towards 4,096 byte blocks. This new sector formatting is called Advanced Format sectors.
To maintain compatibility, Advanced Format media emulates a 512-byte device by maintaining a 512-byte sector at the drive interface. This is important and will eventually be covered in detail in another show. Check with the Forums in the meantime for information on these drives.
By the way, the blocks are done at the factory. This formatting is done during the manufacturing “low level” format. What we do in Disk Management is called “high-level” formatting.
GPT Formatting
Information on UEFI can be found at:
https://moviesgamesandtech.com/2010/11/22/3tb-western-digital-drive-on-a-uefi-day-night/
Realistic Drive Performance
Now, before I start talking numbers here, let me explain something about spindle hard drives:
There is a delay in getting to the data on the drive, and then there is the throughput or the actual writing of the data to the disk. There are many factors when trying to validate the drive performance. All things being equal, you can use the manufacturer specs but your mileage may vary. Tests and benchmarks assume your drive is already spinning and not asleep or in some power saving mode.
Western Digital WD30EZRS Drive Benchmark
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Disk Delays
Three speed measurements Seek Time, Rotational Delay and Transfer Rate.
Seek Time
Think of that record player again. You want to play a song but it is not currently under the needle so the head has to move to it. That move delay is measured in milliseconds but depends on where the head is currently, so try and look for an average seek time. The lower the better, and you want to see around 9ms or less for performance drives.
Rotational Delay
Think of a record player yet again. Once the “needle” has moved you have wait for the start of the song to spin around again on the record. This delay is the same for each RPM class of drives (all 7,200 RPM drives are the same, 5,400 RPM drives etc) so it is really not a comparative number.
Side note: The average ms time has increased over time from 600ms in the 70’s to 20ms in the 80’s to around 4ms on drives currently. These times are based on the RPMs of the drive!
Everything is relative so keep in mind that math shows that the maximum rotational delay of drive spinning 7,200 RPMs a minute is 60/7200, which is 8 milliseconds.
Manufacturers can also say that the “average” of the rotational delay is half of that maximum number so when you see the “average latency” listed on a 7,200 drive is 4.20 ms then you know where it came from!
60 seconds ÷ 7,200 RPMs = .008 – Then take half of that!
Seagate has all of the delay specs on their website while WD does not list delay or random seek times!
Transfer Rates
When talking about transfer rates for drives people typically quote the maximum theoretical cable rate, which is just a simple formula based on the clock rate. You should know that due to file overhead and real life use you will not see those speeds.
In addition, those numbers do not include the drive latencies you will encounter as I just talked about.
Realistic Large File Transfer Speeds Between Drives
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How about an article on managing Basic and Dynamic drives physically and through configurations on WHS Vail. Currently have three satas with something wrong on PHY3/Disk 3. Cannot understand the arrangements WHS has undertaken. Seems to have a mind of it's own.
Vail uses a different file management system and the drive data is not useable outside of Vail. The current beta of Vail includes Drive Extender technology but has since been announced as being removed from Vail. Once a new Vail Beta build is released (maybe next year?) then we will address the drive management. In the current release you should be able to remove the drive and replace it with another. I would then run a utility or chkdsk on it to see if Vail was teh issue or the drive itself.
BACKUP ANY DATA BEFORE REMOVING A DRIVE.