DAS
DAS (Direct Attached Storage) -
a device of external memory connected to a main computer directly and used only by this computer.
The simplest example of DAS is an internal hard drive.
Data recovery
Data recovery -
an activity to recover accidently deleted files or to recover data from the damaged device.
There are data recovery services that work with physically damaged disks and companies which create software to work with logically damaged disks as well.
Data recovery service
Data recovery service -
a company which extracts data from the damaged storage devices.
Data recovery service has a special laboratory (called "clean room") in which it is possible
to manually repair the hard disk without further damaging it.
Data recovery software
Data recovery software -
software to recover accidently deleted files or to recover data from the damaged device.
There are paid and free tools.
Deduplication
Deduplication -
A technology that decreases the disk space usage by eliminating data redundancy.
If there are two identical data blocks on a drive, only one copy is physically stored.
If then it is needed to write new data in one of the blocks, therefore making the blocks different, a filesystem copies the data and modifies the copy.
This technology is called copy-on-write. Deduplication is used in ZFS and BTRFS filesystems.
Defragmentation
Defragmentation - a process of relocating the files so that they are placed contiguously.
The defragmentation increases read and write speed.
Delayed parity
Delayed parity -
a variety of parity blocks placement in RAID 5.
With delayed parity the data block size does not equal to parity block size.
Destriping
Destriping -
the process when data blocks which were striped across different disks are written to a single storage device sequentially.
Typically performed as a part of RAID recovery.
Disk image file
Disk image file - a file containing a copy of data from the storage device.
Disk pool
Disk pool - a set of physical disks from which Storage Spaces allocates its virtual storage.
DIY
DIY -
short for Do It Yourself.
Drobo
Drobo – the company, which produces NAS and DAS devices.
Disks are combined into a single storage using the proprietary storage technique called BeyondRAID.
Dynamic disk
Dynamic disk -
a technology built in Windows which allows to create software RAIDs and to partition disks using LDM.
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