Part Number:RZ29B-VW *
*Click Part Number to Buy or For Pricing Info
Brand: DEC (Digital Equipment Corporation)
Description: Refurbished RZ29BVW 4.3GB SCSI IN SW CANISTER 30 Day Warranty
Call 714-662-4959 or 800-392-6962
Showing posts with label disk. Show all posts
Showing posts with label disk. Show all posts
Sunday, February 19, 2012
RZ29B-E Refurbished DEC SCSI Disk
[caption id="" align="alignleft" width="281" caption="RZ29B-E Refurbished DEC SCSI Disk"]
[/caption]
Part Number: RZ29B-E*
*Click Part Number to Buy or For Pricing Info
Brand: DEC (Digital Equipment Corporation)
Description: Refurbished RZ29BE 4.3GB SCSI DISK DRIVE-BRICK 30 Day Warranty
[/caption]Part Number: RZ29B-E*
*Click Part Number to Buy or For Pricing Info
Brand: DEC (Digital Equipment Corporation)
Description: Refurbished RZ29BE 4.3GB SCSI DISK DRIVE-BRICK 30 Day Warranty
Monday, December 19, 2011
Why the tape media is mostly used for back up purposes?
Tape drives are a form of digital storage devices which use tape for information recording. Because of the cost effective nature of the tape material and their long archival life, tape drives are widely used for backup and archival purposes. A tape drive cannot be accessed randomly like with the hard drives to read a particular piece of data. However, the tape drives can stream data very fast once they are positioned to the particular data point. Because of this factor, tape drives cannot be used for daily storage purposes. There are many formats available for storage of digital information on tape drives. Some of the popular ones are DDS (Digital Data Storage), AIT (Advanced intelligent tape) introduced by Sony and many others. These formats have several generations. AIT is a high speed format for data storage on tapes.
The raw data capacity of tape drives is fixed. However, more amounts of data can be stored on them by using compression. Most of the tape drives have a compression ratio of 2:1. Some tape drives when used with only certain data types can achieve a compression of about 10:1 also. Tape drives can be connected to the computer by using a SCSI interface or other common types as firewire and usb. The reliability according to the recently conducted surveys is not good. Most companies do not test or try to recover from tape archives and some companies that do experienced 77 % failure in achieving a backup of stored data. So, many of the companies in 2011 are starting to move from a tape based back-up solution to a disk based solution.
A large collection of tapes in a huge structure with a mechanical tape loading device is called a tape library. Tape libraries are used for heavy data archival needs like that of financial records of a company. These data facilities take up a lot of money to setup and maintain. A tape library is a digital archive that can store huge amounts of data ranging from several TB to few PetaByte or few 1000 TBs. A trade off exists for higher storage capacities. The access time becomes slower because of mechanical parts and machines when the storage amount increases. Tape autoloaders are tape library devices with a single drive. There are several software technologies for operation of tape libraries. Some of them include open source tape library softwares like AMANDA, Bacula, and the minimal mtx program.
By: Sandeep Mahanthi
The raw data capacity of tape drives is fixed. However, more amounts of data can be stored on them by using compression. Most of the tape drives have a compression ratio of 2:1. Some tape drives when used with only certain data types can achieve a compression of about 10:1 also. Tape drives can be connected to the computer by using a SCSI interface or other common types as firewire and usb. The reliability according to the recently conducted surveys is not good. Most companies do not test or try to recover from tape archives and some companies that do experienced 77 % failure in achieving a backup of stored data. So, many of the companies in 2011 are starting to move from a tape based back-up solution to a disk based solution.
A large collection of tapes in a huge structure with a mechanical tape loading device is called a tape library. Tape libraries are used for heavy data archival needs like that of financial records of a company. These data facilities take up a lot of money to setup and maintain. A tape library is a digital archive that can store huge amounts of data ranging from several TB to few PetaByte or few 1000 TBs. A trade off exists for higher storage capacities. The access time becomes slower because of mechanical parts and machines when the storage amount increases. Tape autoloaders are tape library devices with a single drive. There are several software technologies for operation of tape libraries. Some of them include open source tape library softwares like AMANDA, Bacula, and the minimal mtx program.
By: Sandeep Mahanthi
Can one recover data from a failed drive in RAID 0 array?
RAID stands for redundant array of independent disks. There are various RAID implementations, some built for boosting the performance, some for increasing the redundancy of the data and some others for achieving both. RAID 0 is built solely for performance boosting. In RAID 0, the data is split in to stripes and is stored independently on different drives. The data is read or transferred parallely and this increases the speed of RAID 0 system. Basically, for such a system, redundancy or fail safe is zero or does not exist. In RAID 0, error checking is not implemented. So, one cannot check for errors in his data in a RAID 0 system.
More number of drives increases the speed with which one can access or write data incredibly. But if even one drive fails in a RAID 0 system, the entire information stored on all the three drives is lost because the data is stored in divided blocks. To put it simply, if you are storing a movie file on a RAID 0 system, some part of the movie is stored on drive one, some of it is stored on other drive and remaining part on remaining drives. So, even if one drive fails, one part of your movie is destroyed. And as a result, the integrity of your movie file is disrupted. So, you cannot play the file.
RAID 0 implementation is used in gaming servers where there is no need for a failsafe, but the only need is higher speed. If you notice that one hard drive among your RAID 0 system is failing, you should immediately back up the drive, or remove the drive from RAID 0 system by copying the data on that drives to other drives of RAID 0 system. In this way, one can protect their data from a hard disk failure. In case of a failed hard drive in a RAID 0 system, it is not impossible to recover the data but it is not even easy. The data from the failed hard drive disks can be collected by specialized professionals and some softwares. Then that data can be added to the existing RAID 0 system.
There are other RAID implementations like RAID 1, 2, 3 and so on till 6. Some of these are built strictly for data security such as RAID 1. This implementation needs at least two identical hard drives. RAID 1 mirrors the data stored on one drive on to the other, so that in case of failure, a back-up is immediately available.
By: Sandeep Mahanthi
More number of drives increases the speed with which one can access or write data incredibly. But if even one drive fails in a RAID 0 system, the entire information stored on all the three drives is lost because the data is stored in divided blocks. To put it simply, if you are storing a movie file on a RAID 0 system, some part of the movie is stored on drive one, some of it is stored on other drive and remaining part on remaining drives. So, even if one drive fails, one part of your movie is destroyed. And as a result, the integrity of your movie file is disrupted. So, you cannot play the file.
RAID 0 implementation is used in gaming servers where there is no need for a failsafe, but the only need is higher speed. If you notice that one hard drive among your RAID 0 system is failing, you should immediately back up the drive, or remove the drive from RAID 0 system by copying the data on that drives to other drives of RAID 0 system. In this way, one can protect their data from a hard disk failure. In case of a failed hard drive in a RAID 0 system, it is not impossible to recover the data but it is not even easy. The data from the failed hard drive disks can be collected by specialized professionals and some softwares. Then that data can be added to the existing RAID 0 system.
There are other RAID implementations like RAID 1, 2, 3 and so on till 6. Some of these are built strictly for data security such as RAID 1. This implementation needs at least two identical hard drives. RAID 1 mirrors the data stored on one drive on to the other, so that in case of failure, a back-up is immediately available.
By: Sandeep Mahanthi
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