Raid 1 + 0 - can fail too

Raid 10

You have a failed Raid 10 : Make Sure all drives are numbered and clearly marked

RAID 10 is implemented as a striped array whose segments are RAID 1 arrays

RAID 10 has the same fault tolerance as RAID level 1

RAID 10 has the same overhead for fault-tolerance as mirroring alone

High I/O rates are achieved by striping RAID 1 segments

Under certain circumstances, RAID 10 array can sustain multiple
simultaneous drive failures

Excellent solution for sites that would have otherwise gone with RAID 1
but need some additional performance boost


But did you know:

All drives must move in parallel to proper track lowering sustained
performance

Very limited scalability at a very high inherent cos




*Questions for the reader:


How many drives have failed? are they logical, electrical or physical
failures. Are the drives a matched set. Do you know if the failure of
the two drives was at the same time or has one drive failed and the
second went out at a later date?

Keep the order of the drives - number them before removing any drives.

Has the Raid been reinitialised? - if not DO NOT allow a reinitialisation

Are you able to supply the Raid controller?

Capacity of the drives (how many GB for each drive)
What type of drives (IDE ,SCSI, SATA)

Block Size used? (offset of starting block)
Details - additional RAID information

5 Essential Tips For Your RAID5

5 Essential Tips For Your RAID5

As the cost of drives become cheaper, and capacity is expanded, it is not surprising to find the popularity of RAID5 systems increasing.

However, like any other computer component, they are subject to failure.

Follow these essential tips to ensure you keep your RAID running smoothly, and your data intact.

1 - Backup Regularly

RAID5 is not a substitute for regular proven backups.

RAID5 cannot prevent problems occurring from deleted or overwritten files, formatted partitions, file structure damage, virus activity or user error.

RAID5 is designed to be hardware fault tolerant, not software fault tolerant.

Restoring from your backups is sometimes the only method of recovering from logical data problems.

Also, do not backup from your RAID5 to another file, directory or partition on your RAID5 - if your entire RAID5 fails over, so does your entire data set.


2 - Maintain Drive Comfort

Multiple drives all spinning concurrently can generate a lot of heat.

Be liberal with your cooling methods, a single fan is the absolute minimum, better to have a fan blowing through the spacing between the drives, and a second fan helping to exhaust the warm air.

Also be diligent in dusting out your enclosure as computer fans have a nasty habit of bringing any outside dust inside the case where it can settle on components, raise temperatures and cause electrical damage.


3 - Monitor RAID Status

Most major software RAID programs and hardware RAID card manufacturers can create logs detailing all sorts of useful information on your RAID.

Ranging from performance values to outright failure notification, it is wise to use these logs to your advantage

For example, they can inform you that a drive has been dropped from the array perhaps through a bad data cable and is no longer detecting.

Without any warning you may not notice this failure since your RAID will simply continue running in degraded mode until the problem is repaired.

Extra tip: Setup a periodic, automatic email of the log files to your email account to ensure that you are on top of any problems that may arise during the day to day running of the system.


4 - Keep A Spare Identical Drive

It is only a matter of time before a drive in your RAID5 starts to degenerate with read errors, or fails entirely due to motor failure or the click of death.

Thanks to RAID5 reliability you can counter this by replacing the failed drive without too much effort.

Before, you simply power down and replace the drive (or hotswap) ensure your backups are in working order, because Murphy is currently eyeing your RAID which now has zero tolerancy for failure.

Replacing the drive with the exact same model will ensure the same performance from your RAID as before the failure occurred.

Secondly, if your RAID does happen to sustain a multiple drive failure from which you cannot recover, a power surge comes immediately to mind, having a spare drive readily available for parts for a specialist data recovery laboratory may save you time and money.


5 - Label Your Drives

When it does come time to replace a drive in your array, it pays to know the exact one you should be replacing.

More often than not further problems are caused by accidently replacing an incorrect drive, which can 'confuse' many controllers - even after drive order is returned.

Do yourself a favour and label the drives as they are marked in the controller card or software configuration you use.

http://www.sydneydatarecovery.com.au/raid-recovery.html

Raid 0 – failed? needing answers!

Raid 0 – failed needing answers call or online

http://australiadatarecovery.com.au/raid-0-data-recovery/


You have a failed Raid 0 :

You set it up for speed- RAID 0 implements a striped disk array, the data is broken down into blocks and each block is written to a separate disk drive,

Raid 0 - I/O performance is greatly improved by spreading the I/O load across many channels and drives

Raid 0 -Best performance is achieved when data is striped across multiple controllers with only one drive per controller

Raid 0 -Very simple design and was easy to implement

all this you may know but did you read the Small print for your Raid 0 -:

* The failure of just one drive will result in all data in an array being lost*

* Should never be used in mission critical environments


*Questions for you:

If there is 1 failed drive is it a logical failure or a physical failure. Any unsual noises remove the power immediately and completely.

Are the 2 hard drives a matched set - this can sometimes help in the speed of turn around as parts can be utilized from the good drive to bring the failed drive up to spec.

Or at the very least in a state that data can be mirrored.

The lab will require both hard drives sent in and can do a lab evaluation and quote same day of its arrival.

The quote will let you know the firm quote and time required to get your data back to you.