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Certifying disks before you use them

Manufacturers don't test their disks

When you buy a disk, how can you know if it's faulty? You'd think that disk manufacturers would test every sector on a disk before they shipped it, but unfortunately, they don't. It would take them too long. With SoftRAID, you can perform the testing that disk manufacturers can't afford to do.

SoftRAID's certify feature can tell you if you have a faulty disk before you put precious data on it. When you certify a disk with SoftRAID, you read and write to every sector of the disk, more than once.

certifying a disk with softraid

SoftRAID writes a random pattern out to every sector and then reads and verifies the pattern to make sure every sector on the disk is reliable. Once it has tested every sector, you can have SoftRAID start another pass through the disk.

You can perform up to 8 passes when certifying a disk—we recommend at least 3. To 'recondition' an SD card you will need at least 2 certify passes.

Without certifying, your data is at risk

Certifying a large disk with SoftRAID can take a day or two but it's worth it! After you have certified a disk, you know that it can safely and reliably store your files.

If you don't take the time to certify a disk, you run the risk of losing all the data you put on it.

Certify more than one disk at a time

You can certify many disks at once. On Thunderbolt buses, certifying 4 - 8 disks at once takes only slightly longer than certifying a single disk.

Certify your SSDs as well as your HDDs

SoftRAID doesn't just certify rotating drives. You can use SoftRAID's certify feature to test new SD memory cards before you use them in your digital camera, video recorder etc. Whether it's an SD, SDHC, or SDXC card, SoftRAID will let you know if your new card has any bad sectors on it that could put your data at risk. Remember to use at least 2 certify passes; 3 is even better.

Use certify to "revitalize" your SD cards

It's a good idea to regularly "revitalize" or "recondition" your SD memory cards, and SoftRAID's certify can help you do that.

SSDs that don't use TRIM (such as all USB flash media) get slower the more they are used, because instead of actually erasing old data, flash just labels those sectors as "clean". When you need to write to these previously used sections, data has to be erased first, slowing the process down. In addition, the more you write to an SD, the harder it is to find 'clean' areas to write to.

Certifying your SD card will fill the memory with zeros, essentially 'erasing' all the data, and making it behave like new. However, always remember that certifying will erase all the data from your drive, so be sure to back up your data first. (It's not possible to restore data from a card that's been certified as the data has been overwritten with zeros.)

Note: You must use at least a 2 pass certify on any SSD or SD media to recondition the memory.

Verifying disks with volumes on them

If you want to test a disk without destroying the volumes on it, you can use SoftRAID to verify the disk. When you verify a disk, SoftRAID will read every sector on the disk to ensure that it can be read without errors.

certifying a disk with softraid

If you encounter errors while verifying a disk, you should check the cables and power supply for your disk. If you can't find any problems with them, you should replace the disk immediately. Even a single unreadable sector indicates that the disk might be about to fail completely.

Validating SoftRAID Volumes

If you are ever concerned about the integrity of your SoftRAID volume, you can - at any time - validate it, to make sure all the data on it is still readable. During the validation process, SoftRAID will read every block on the volume to make sure it can be read without errors. If there is an error, the SoftRAID Monitor will warn you and will add an entry to the SoftRAID log file. The validation process will also run extra checks depending on the type of volume you have (see RAID level validation details below).

The actual validating of the volume is done by the SoftRAID driver, so you can start the validation process, quit the SoftRAID application and the validation process will keep going. You can continue to use your volume normally while the driver is validating it. You can even validate your startup volume.

While it's validating a volume, the driver watches to see if you're using the volume. If the driver sees that you have started to read or write files on the volume, it stops validating for a second or two. Then it resumes validating the volume where it left off.

Validating a SoftRAID Mirror or RAID 1+0 volume

When SoftRAID validates a mirror or RAID 1+0 volume,1 it reads from each disk in a mirror set and compares the data. If the data from all the disks in a mirror (RAID 1) or mirror set (RAID 1+0) do not match, SoftRAID updates the disks so they are all identical to their mirrored twin.

Validating a RAID 4 and RAID 5 volume

When SoftRAID validates a RAID 4 or RAID 5 volume,1 it reads the data for each block and recalculates the parity information. It then compares the recalculated parity information with the parity information stored on the disks. If the parity information on the disks is incorrect, SoftRAID updates the disks with the correct parity information.

Validating for peace of mind

Validating a volume is not required, but it's a good safety measure. You can think of it like checking the pressure on your spare tire; if you get a flat you have the peace of mind that your spare is ready to go. Validation gives you the peace of mind that if any problem occurs, all the parity and mirror data is correct and up-to-date.

Testing disks with SMART2

The SoftRAID application performs a SMART test on every disk each time you run it.3 In addition, the SoftRAID Monitor runs a SMART test on every disk each time you start up your Mac. It also runs the SMART test every 24 hours while your Mac is running.

SMART testing a disk with softraid

During a SMART test, the disk tests itself to make sure it is operating correctly. If the disk determines that some part of the mechanical mechanism or electronics is not working correctly, it will fail the SMART test. Disks which fail the SMART test should be replaced immediately.   

1. RAID 4, 5 and 1+0 volumes are not supported in SoftRAID Lite. back...

2. SMART is a monitoring system in disk drives that SoftRAID's Monitor uses to assess drive reliability and anticipate drive failures. back...

3. This features require disks which support SMART. They are not available on disks connected via USB or FireWire and may not be available if a disk is connected via some third party interface cards. back...