Newsgroup: it.comp.hardware.scsi
Titolo: Salve!! ;-)

Dunque ora tocca a me:
sebbene mi debba spacciare per un riparatore di PC anche scsi, non mi sono
mai posto il problema di configurare una Raid per un solo disco fisso, la
raid in questione e quella dell'ibm, che si trova nei Netfinity con un  solo
disco fisso IBM.
Come si fa??
se qualcuno dovesse avere anche solo i manuali o gliURL degli stessi mi
arrangio io, comunque grazie in anticipo
Antanio Ze Best!!!

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news:83e1ta$g2u$1...@pinco.nettuno.it...
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Quindi raid funziona solo con due dischi alla volta, io sapevo invece
dell'esistenza di 3 modi per scsi modo 0 1 2,  dove lo 0 consisteva nel
dimezzare lo spazio sia su due dischi di modo da creare un backup continuo,
appunto per sopperire alla rottura, mentre il modo 1 raddoppiava la
dimensione del disco;
comunque ribadisco che scsi in quest termini mi si presenta per la prima
volta.
Nel caso in cui io gli voglia montare un ,masterizzatore???
Fra ha scritto nel messaggio ...
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riporto solo quanto letto altrove:
What is RAID?
RAID is an acronym for Redundant Array of Inexpensive (or
Independent) Disks. A RAID array is a collection of drives which
collectively act as a single storage system, which can tolerate
the
failure of a drive without losing data, and which can operate
independently of each other.
What are the different RAID levels?
A research group at UC-Berkeley coined the term "RAID", defining
six
RAID levels. Each level is a different way to spread data across
multiple drives, a compromise between cost and speed.
Understanding
these levels is important, because each level is optimized for a
different
use.
RAID Level 0
RAID Level 0 is not redundant, hence does not truly fit the
"RAID" acronym. In level 0, data is split across drives,
resulting
in higher data throughput. Since no redundant information is
stored, performance is very good, but the failure of any disk in
the array results in data loss. This level is commonly referred
to
as striping.
RAID Level 1
RAID Level 1 provides redundancy by duplicating all data from
one drive on another drive. The performance of a level 1 array is
only slightly better than a single drive, but if either drive
fails, no
data is lost. This is a good entry-level redundant system, since
only two drives are required; however, since one drive is used to
store a duplicate of the data, the cost per megabyte is high.
This
level is commonly referred to as mirroring.
RAID Level 2
RAID Level 2, which uses Hamming error correction codes, is
intended for use with drives which do not have built-in error
detection. All SCSI drives support built-in error detection, so
this
level is of little use when using SCSI drives.
RAID Level 3
RAID Level 3 stripes data at a byte level across several drives,
with parity stored on one drive. It is otherwise similar to level
4.
Byte-level striping requires hardware support for efficient use.
RAID Level 4
RAID Level 4 stripes data at a block level across several drives,
with parity stored on one drive. The parity information allows
recovery from the failure of any single drive. The performance of
a level 4 array is very good for reads (the same as level 0).
Writes, however, require that parity data be updated each time.
This slows small random writes, in particular, though large
writes
or sequential writes are fairly fast. Because only one drive in
the
array stores redundant data, the cost per megabyte of a level 4
array can be fairly low.
RAID Level 5
RAID Level 5 is similar to level 4, but distributes parity among
the drives. This can speed small writes in multiprocessing
systems, since the parity disk does not become a bottleneck.
Because parity data must be skipped on each drive during
reads, however, the performance for reads tends to be
considerably lower than a level 4 array. The cost per megabyte
is the same as for level 4.
-----------------------------------------------------------------
--------------------
********RAID Level Uses**********
Level 0 (striping)
Any application which requires very high speed storage, but
does not need redundancy. Photoshop temporary files are a
good example.
Level 1 (mirroring)
Applications which require redundancy with fast random writes;
entry-level systems where only two drives are available. Small
file servers are an example.
Level 4 (parity)
Applications which require redundancy at low cost, or with
high-speed
reads. This is good for archival storage. Larger file
servers are an example.
Level 5 (distributed parity)
Similar to level 4, but may provide higher performance if most
I/O is random and in small chunks. Database servers are an
example.
N.B. Often, it makes sense to use more than one level. For
instance, in a
two-drive system, one partition could use level 0 to offer the
highest
performance for temporary files; another partition could use
level 1 to
offer security for important data or applications. In a
three-drive system,
a partition for temporary files could use level 0, the boot disk
could use
level 1, and large data files could be stored on a level 4
partition.
Scusate la lunghezza ma mi sembra chiaro ed esauriente
________________________________
Saluti e .... alla prossima !!!
°°° Gascho °°°    §;-)
________________________________

Qui c'è un link su netfinity, dacci uno sguardo
http://www.pc.ibm.com/us/netfinity/netfinity.html
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Un link più specifico:
http://www.pc.ibm.com/support?lang=en_US&page=brand&brand=IBM+PC+
Server&doctype=Online+publications&family=
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>credo che ti stai sbagliando.......
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