Glyph cy-misan-v ユーザーガイド
168
Cybernetics
UM-MV-86-B1-0801
CHAP – “Challenge-Handshake Authentication Protocol” (CHAP) is a scheme that uses a
3-way “handshake” (peer-response-authenticator) to periodically verify the identity of the
peer (iSCSI host initiator). Authentication begins after a network link is established and
the authenticator (iSCSI target; iSAN Vault) sends a “challenge” message to the peer.
The peer responds with a calculated value that embeds a “secret” (user password). The
authenticator checks the response value against its own expectation. If the value
matches, the peer is then authenticated (logged on to the iSAN Vault).
3-way “handshake” (peer-response-authenticator) to periodically verify the identity of the
peer (iSCSI host initiator). Authentication begins after a network link is established and
the authenticator (iSCSI target; iSAN Vault) sends a “challenge” message to the peer.
The peer responds with a calculated value that embeds a “secret” (user password). The
authenticator checks the response value against its own expectation. If the value
matches, the peer is then authenticated (logged on to the iSAN Vault).
Compression – Compression reduces the amount of storage space required to store a
given amount of data. The miSAN-V-Series is incapable of compressing data while writ-
ing to virtual tapes. Data compression is only performed by a physical tape drive when
the miSAN-V-Series writes to physical tape. The “Drive compression for copying” menu
option toggles internal tape drive data compression for all attached tape devices.
given amount of data. The miSAN-V-Series is incapable of compressing data while writ-
ing to virtual tapes. Data compression is only performed by a physical tape drive when
the miSAN-V-Series writes to physical tape. The “Drive compression for copying” menu
option toggles internal tape drive data compression for all attached tape devices.
Copy Profile – Copy profiles allow the user to define and save relationships between vir-
tual tapes and physical tapes slotted inside the physical stacker. For example, the first vir-
tual tape will always be copied to the first physical tape, the second virtual tape to the
second physical tape, the third virtual tape to the third physical tape and so forth. Using
copy profiles saves from manually having to select virtual tapes to copy each time
“Offload disk to tapes” is enabled.
tual tapes and physical tapes slotted inside the physical stacker. For example, the first vir-
tual tape will always be copied to the first physical tape, the second virtual tape to the
second physical tape, the third virtual tape to the third physical tape and so forth. Using
copy profiles saves from manually having to select virtual tapes to copy each time
“Offload disk to tapes” is enabled.
D2D2T – Disk-to-Disk-to-Tape (D2D2T) is an approach to computer backup and
archiving in which data is initially copied to a disk storage device and then periodically
copied again to a tape storage device (or to an optical disc drive).
archiving in which data is initially copied to a disk storage device and then periodically
copied again to a tape storage device (or to an optical disc drive).
Daisy-chaining – Connecting multiple devices one to another in a series.
Distributed Parity – Parity works in combination with striping on RAID 5 and RAID 50.
Parity information is written to each of the striped drives, in rotation. Should a failure
occur, the data on the failed drive can be reconstructed from the data on the other drives.
Parity information is written to each of the striped drives, in rotation. Should a failure
occur, the data on the failed drive can be reconstructed from the data on the other drives.
ECC – Error-Correcting Code (ECC) is integrated into many tape drives for the purpose
of reconstructing data bits missing from the tape as a result of tape quality degradation.
The number of ECC occurrences since the last tape rewind is calculated as a percentage.
In general, error rates are the highest at the beginning of a tape since this part of the tape
is written to every time the tape unloads.
of reconstructing data bits missing from the tape as a result of tape quality degradation.
The number of ECC occurrences since the last tape rewind is calculated as a percentage.
In general, error rates are the highest at the beginning of a tape since this part of the tape
is written to every time the tape unloads.
Host I/O – The HSTC’s disk drive input and output (disk I/O) resources used by hosts for
backup and restore jobs. Both host I/O resources and job I/O resources draw from the
same disk I/O resources. Thus, one impacts the other’s performance. You can use the
“Host vs. job I/O policy” setting to determine the priority of host I/O relative to job I/O.
backup and restore jobs. Both host I/O resources and job I/O resources draw from the
same disk I/O resources. Thus, one impacts the other’s performance. You can use the
“Host vs. job I/O policy” setting to determine the priority of host I/O relative to job I/O.
Hot Swap – The process of swapping out a drive without having to shut down the system.
This is useful when you need to swap out a degraded drive, manually or automatically,
with a pre-designated spare.
This is useful when you need to swap out a degraded drive, manually or automatically,
with a pre-designated spare.
HSTC – High Speed Tape Cache (HSTC) is a software engine that emulates conven-
tional tape drives and tape cartridges. Host applications use HSTC virtual tapes and
drives as conventional backup resources.
tional tape drives and tape cartridges. Host applications use HSTC virtual tapes and
drives as conventional backup resources.
iSCSI – Internet SCSI (iSCSI) is a method of transmitting SCSI commands, data and sta-
tus across Ethernet-based standard TCP/IP networks. This allows SCSI devices and
SCSI-aware software (e.g., backup applications) to communicate remotely via existing
networks.
tus across Ethernet-based standard TCP/IP networks. This allows SCSI devices and
SCSI-aware software (e.g., backup applications) to communicate remotely via existing
networks.