Commissario
Ok, this is a quick and dirty FAQ for the new forum (at least until I or someone else can get round to doing a better one).
It covers a lot of the most common questions asked about drives, so don't be suprised if someone has told you to read it.
Drive utilities, RAID information,Manufacturers support/RMA pages, and common questions/problems.
Backup's are your friend
I'm sure that no one will ever read this, but i'll say it any way.
Always keep backups of your important data - just because your hard drive is "fine today" doesn't mean you won't need to recover data tommorow (due to virus, drive failure or partion gone wrong).
A CDRW Drive can be bought for about £30, CDR's can be bought for as little as 12p each, DVD writers can be bought for £100 and DVD-R can be bought for £1 each.
Compare this to the cost of recovering your data using a specialist program (can cost £100's assuming it works), or to hire a specialist company to do the data recovery (can cost thousands).
There are very good reasons programs like Partition Magic tell you to back up your data, they can and do go wrong on occassion - which can cause you to lose a partitions worth of data.
Yes it can be annoying backing up your data but lets face it, 8 minutes once a month will probably back up all your "documents", your email folders and your favourites.
If you are doing coursework/Uni project do a backup to CDR every week, and a daily backup to CDRW (if you've got webspace use that as well), it'll cost you maybe a fiver over the space of a year, which is nothing compared to having to redo all your work.
Other options for backups include:
There is no excuse for not having a backup of your data in this day and age, mass storage has never been this cheap.
Many thanks to Exentia for updating the sticky, and all those who made suggestions
It covers a lot of the most common questions asked about drives, so don't be suprised if someone has told you to read it.
Drive utilities, RAID information,Manufacturers support/RMA pages, and common questions/problems.
Backup's are your friend
I'm sure that no one will ever read this, but i'll say it any way.
Always keep backups of your important data - just because your hard drive is "fine today" doesn't mean you won't need to recover data tommorow (due to virus, drive failure or partion gone wrong).
A CDRW Drive can be bought for about £30, CDR's can be bought for as little as 12p each, DVD writers can be bought for £100 and DVD-R can be bought for £1 each.
Compare this to the cost of recovering your data using a specialist program (can cost £100's assuming it works), or to hire a specialist company to do the data recovery (can cost thousands).
There are very good reasons programs like Partition Magic tell you to back up your data, they can and do go wrong on occassion - which can cause you to lose a partitions worth of data.
Yes it can be annoying backing up your data but lets face it, 8 minutes once a month will probably back up all your "documents", your email folders and your favourites.
If you are doing coursework/Uni project do a backup to CDR every week, and a daily backup to CDRW (if you've got webspace use that as well), it'll cost you maybe a fiver over the space of a year, which is nothing compared to having to redo all your work.
Other options for backups include:
- Second hard drive -either on another machine, in RAID 1, or as a seperate drive in the same machine (but remember a second hard drive in the same machine might be killed at the same time as the primary if you have a power surge or PSU failure)
- External/removable hard drive
- USB/flash/smart media type memory sticks
- Floppy drive + floppies
- Webspace (good idea for students etc, place your latest version of your coursework on your webspace in a location you can remember - you'll have it if you need it at school/uni or if you have a drive failure)
- CDR/CDRW a CDRW drive can be had for £25-30
- DVDR - DVDR drives can now be found in the £100 price range and will hold ~4.5gb per disk
There is no excuse for not having a backup of your data in this day and age, mass storage has never been this cheap.
Exentia said:I was just reading through the sticky and realised how old it is, so ive gone through it quickly and updated and added some stuff while i had some spare time. If anybody knows of anything that may be a good addition to it then let me know, you never know this may get added to the sticky!
Anyway here it is:
HITACHI
Support can be found here.
For warranty checks, RMA process and info go here.
Hitachi's Data recovery policy and info is found here.
Hitachi's Download and Driver section is found here.
Hitachi jumper settings can be found here.
MAXTOR
Support can be found here.
For warranty checks and RMA process and info go to here.
Maxtors's Data recovery policy and info is found here.
Maxtor's Download and Driver section is found here.
Maxtor jumper settings can be found here.
SAMSUNG
Support can be found here.
For warranty checks and RMA process and info go to here.
Samsung's Hard drive FAQ and other tools can be found here.
Samsung's Download and Driver section is found here.
Samsung jumper settings can be found here.
SEAGATE
For Seagate's warranty checks and RMA process go here.
Seagate's Data Recovery Service and info can be found here.
Seagate's Download and Driver section can be found here.
For support, jumper info and technical details go to here.
WESTERN DIGITAL
Support can be found here.
Western Digital's Download and Driver section can be found here.
For warranty checks and RMA process and info go to here.
Western Digital's Data Recovery info can be found here.
For jumper info go to here.
Fdisk and Partitioning Guides
http://members.aol.com/don5408/drivespace/fdisk.html
http://www.5starsupport.com/tutorial/format.htm
http://fdisk.radified.com/
http://www.newlogic.co.uk/kbase/fdisk/page1.htm
Hard Drive review and info sites
http://www.storagereview.com/
http://exentia.atspace.com (well I couldnt not pimp my own site could I?)
Definition of Terms
Interface:
The interface by which the drive is connected to the controller, available options:
PATA 33/66/100/133
SATA 150/3GB
SCSU Ultra 1,2,160,320
USB 1,1.1,2
Firewire 400,800
Capacity:
The capacity of the drive in gigabytes (Gb)
Companies go by 1000 MB = 1GB instead of 1024MB =1GB
so when you see a drive with say 120GB it in fact is 111GB (formatted)
Cache:
The drives own solid state data buffer area, most drives have 2,8 or 16MB of cache
RPM:
The speed at which the drive's platters rotate, generally, the faster the RPM, the faster the drive
Average Read:
The average speed which data can be read off the drive. measured in megabytes per second (MB/s) Higher is better
Access Time:
The time it takes to access any random block of data on the drive, measured in milliseconds (1/1000th second) (ms). Lower is better
Burst:
This is the maximum theoretical speed at which the drive can communicate with the controller bus, higher is better. Measured in megabytes per second (MB/s)
(Taken from my Site but made by Smiley Man, it can be found here )
RAID information and definitions
Basic RAID definitions
JBOD. JBOD is NOT RAID. JBOD stands for 'Just a Bunch Of Disks'. This accurately describes the underlying physical structure that all RAID structures rely upon. When a hardware RAID controller is used, it normally defaults to JBOD configuration for attached disks.
Some disk controller manufacturers incorrectly use the term JBOD to refer to a Concatenated array.
Concatenated array. A Concatenated array is NOT RAID, although it is an array. It is a group of disks connected together, end-to-end, for the purpose of creating a larger logical disk. Although it is not RAID, it is included here as it is the result of early attempts to combine multiple disks into a single logical device. There is no redundancy with a Concatenated array. Any performance improvement over a single disk is achieved because the file-system uses multiple disks. This type of array is usually slower than a RAID-0 array of the same number of disks.
RAID-0. This technique has no redundancy of data. It offers the best performance but no fault-tolerance whatsoever. If you lose one drive, the whole array will fail. At least 2 drives needed
RAID-1. This type is also known as mirroring and consists of at least two drives that contain duplicates of your data. There is no striping for extra write performance but read performance is improved since either disk can be read at the same time. At least 2 drives needed
RAID-2. This type uses striping across disks with some disks storing error checking and correcting (ECC) information. It has no advantage over RAID-3. Hardly ever used. At least 5 drives needed (I think)
RAID-3. This type uses striping and dedicates one drive to storing parity information. The embedded error checking (ECC) information is used to detect errors. Data recovery is accomplished by calculating the exclusive OR (XOR) of the information recorded on the other drives. Since an I/O operation addresses all drives at the same time, RAID-3 cannot overlap I/O. For this reason, RAID-3 is best for single-user systems with long record applications. At least 3 drives needed.
RAID-4. This type uses large stripes, which means you can read records from any single drive. This allows you to take advantage of overlapped I/O for read operations. Since all write operations have to update the parity drive, no I/O overlapping is possible. RAID-4 offers no advantage over RAID-5. At least 3 drives needed.
RAID-5. This type includes a rotating parity array, thus addressing the write limitation in RAID-4. Thus, all read and write operations can be overlapped. RAID-5 stores parity information but not redundant data (but parity information can be used to reconstruct data). RAID-5 requires at least three and usually five disks for the array. It's best for multi-user systems in which performance is not critical or which do few write operations. The maximujm usable capacity of a RAID 5 array is (Size of Smallest Drive) * (Number of Drives - 1). You could use 1*10gb and 2*20gb drives in a RAID 5 array but only 20gb would be usable (30 gb total for 3 drives - 10gb). You can run a RAID 5 array with 11 disks, but only the capacity of 1 would be used for parity. This would mean that the array could only tolerate the loss of 1 disks worth of data, in other words, not massivley reliable. At least 3 drives needed.
RAID-6. This type is similar to RAID-5 but includes a second parity scheme that is distributed across different drives and thus offers extremely high fault- and drive-failure tolerance. There are few or no commercial examples currently. With RAID 6 usable capacity the capacity of all the drives is (Size of Smallest Drive) * (Number of Drives - 2). A RAID 6 array can tolerate the loss of 2 drives unlike RAID 5. 4 drives required minimum.
RAID-7. This type includes a real-time embedded operating system as a controller, caching via a high-speed bus, and other characteristics of a stand-alone computer. One vendor offers this system. RAID 7 is the fastest RAID array. Because this generally a bespoke solution, the number of drives required varies.
RAID-10. This type offers an array of stripes in which each stripe is a RAID-1 array of drives. This offers higher performance than RAID-1 but at much higher cost. At least 4 drives needed.
RAID-53. This type offers an array of stripes in which each stripe is a RAID-3 array of disks. This offers higher performance than RAID-3 but at much higher cost. At least 6 drives needed.
Compound RAID definitions
There are times when more then one type of RAID must be combined, in order to achieve the desired effect. In general, this would consist of RAID-0, combined with another RAID level (I've seen RAID-1, RAID-3 and RAID-5 used with RAID-0).
The primary reason for combining multiple RAID architectures would be to get either a very large, or a very fast, logical disk.
The list below contains a few examples. It is not the limit of what can be done.
RAID-1+0. RAID Level 1+0 (also called RAID-10) is the result of RAID-0 applied to multiple RAID-1 arrays. This will create a very fast, stable array. In this array, it is possible to have multiple disk failures, without loosing any data, and with a minimum performance impact.
To recover from a failed disk, it is necessary to replace the failed disk, and rebuild that disk from its mirror.
For two-drive failures, the probability of survival is 66% for a 4-disk array, and approaches 100% as the number of disks in the array increases.
RAID-0+1. RAID Level 0+1 is the result of RAID-1 applied to multiple RAID-0 arrays. This will create a very fast array. If the RAID-0 controllers (hardware or software) are capable of returning an error for data requests to failed drives, then this array has all the abilities of RAID-10. If an entire RAID-0 array is disabled when one drive fails, this becomes only slightly more reliable then RAID-0.
To recover from a failed disk, it is necessary to replace the failed disk, and rebuild the entire RAID-0 array from its mirror. This requires much more disk I/O than is required to recover from a disk failure in RAID-10. It should be noted that some enterprise-level RAID controllers are capable of tracking which drives in a RAID-0 array have failed, and only rebuilding that drive. These controllers are very expensive.
For two-drive failures, the probability of survival is 33% for a 4-disk array, and approaches 50% as the number of disks in the array increases.
This RAID level is significantly less reliable than RAID-1+0. This is because the structure is inherently less reliable in a multi-disk failure, combined with the longer time to reconstruct after a failure (due to a larger amount of data needing to be copied). The longer time increases the probability of a second disk failing before the first disk has been completely rebuilt.
RAID-3+0. RAID Level 3+0 is the result of RAID-0 applied to multiple RAID-3 arrays. This will improve the performance of a RAID-3 array, and allow multiple RAID-3 arrays to be dealt with as a single logical device. RAID-3+0 has a reliability similar to RAID-3, with improved performance.
This type of array is most commonly found when combining multiple hardware RAID devices into a single logical device.
RAID-5+0. RAID Level 5+0 (also called RAID-53 for some unknown reason) is the result of RAID-0 applied to multiple RAID-5 arrays. This will improve the performance of a RAID-5 array, and allow multiple RAID-5 arrays to be dealt with as a single logical device. The reliability of this type of array is similar to that of a RAID-1+0 array, but it has the performance impacts of RAID-5.
This type of array is most commonly found when combining multiple hardware RAID devices into a single logical device.
RAID-3+3+0. I saw this in 1992. This extreme measure was done to achieve a very high transfer rate on the swap partition of a Cray supercomputer. Using the RAID configuration below, the 4GB of memory could be transferred to disk in under 11 seconds. I include it here as an example of what can be done.
The individual disk drives (they were Seagate ST82368K) had a rudimentary RAID-3 controller built into them, where the individual data bits were routed to different heads, and the parity bit was routed to yet another head. Since the drive had eighteen physical heads, it was configured for two logical heads. The disk was capable of correcting for a bad head, but was not able to rebuild the data after the failed head was repaired (usually, a failure on a head amplifier card). This drive was capable of transferring 24MB/S sustained, which was excellent for the time (a fast SCSI drive could rarely sustain more than 3MB/S).
The individual drives were combined in a RAID-3 4+1 array, using a hardware controller. This was a full implementation of RAID-3, and could rebuild a drive, if necessary. This allowed a failed drive to be removed, and repaired, without damaging the array. This portion of the array was capable of transferring 96MB/S sustained.
The RAID-3 arrays were combined in a RAID-0 4-wide array, in software. This gave a sustained transfer rate of 384MB/S to the array.
definitions borrowed from whatis.com and accs.com
Stripe Sizes A Simple Breakdown
4k Stripe - The smallest stripe available on many controllers. This size has a very high benchmarking performance. Infact it has the highest. If you want to see what your rig can do try this and benchmark it. However!, real-world performance is quite bad, infact the small stripe increases overhead reading so much that when dealing big games or graphic manipulation, performance suffers. Not a recommended day to day setting
16/32/64k Stripe - These three settings are useful for the casual user who does not handle big files. Benchies reflect an excellant STR and any OS will feel very responsive. I would say this is an opimum setting the user who surfs, plays the occasional game and likes windows to be nice and snappy. Obviously the variance depends on what kind of files you predict that you will use but it all comes from trying and experimenting.
128/256k Stripe - 128k is aparently the optimum stripe size for Intel's 'average' user. It provides a pretty high STR but keeps performance constantly high even when dealing with larger files. Users who rely on photoshop or compliation apps will like a 256k stripe due to the larger files that need to be chucked around. Of course the larger the stripe, the less CPU time used. This could be a big disadvantage for smaller stripes.
When chosing your stripe, just remember that Smaller stripe size= better transfer rate = less HDD performance
This was taken from the thread in the General Hardware Archive and was written by ColdFusion it can be found here.
SATA and RAID installation guides
http://www.seagate.com/support/kb/disc/howto/sata_install_tshoot.html
Testing Utilities
Sisoft Sandra
HDTach
HDTune
IOzone
Many thanks to Exentia for updating the sticky, and all those who made suggestions
