AKO JE TO S RAID 0,1

[Miro Bobovsky]

Takze SATA RAID .....

trochu som sa s tym natahoval tiez ..
Preco moze vzniknut ze ide ozaj o HW raid .. :
a,
lebo ak naistalujes MSDOS tak ho ziadny extra driver nedavas a proste mas pocit 
ze mas jeden disk a pritom su dva a je medzi nimi napr mirror (nastavis v 
biose)
Ibaze ..realita je tvrda .. pozornejsi clovek zisti ze karticka ma boot bios 
epromku (podobne ako video karty) a pre dos tam uz nejaky driver je ale beztak 
to robi tvoj CPU ale nie jednocip na radici ako to bolo pri SCSI ozaj HW 
raidoch.
b,
Windows .. zase moze dojst k pocitu ze sa jedna ozaj o HW raid lebo win nic 
nespoznaju a treba im dat driver (cez flopak z coho ma skoro porazilo) ale 
potom uz to vidis len ako jeden disk a mozes mat zase dojem ze ide o ozaj HW 
raid .. Ibaze ...
Nainstalovali sme win na mirror (aj sa to pytal) proste vsetko prebehlo super 
..
Ibaze .. ak sme nasledne vybrali druhy disk a bootli tak to slapalo ale ak sme 
po naistalovani a naslednom reboote vybrali druhy disk tak smola ..data boli v 
prdeli lebo na druhom disku este akosi nebolo vsetko (hoci prebehol koretkny 
shutdown) a uz ani spojenie a nejaky pokus o repair nemal sancu lebo ako 
aktivny uz bol disk co mal zle data a pri zapnuti oboch posral aj byvali prvy 
disk .. proste ... tragedia
Potom cez nejake scsi utility sme nasli nejaky monitor a ten vravel po 
naistloani ze 5% do nejakeho stavo ked bude "hotovo" a teda o 3 hodiny ked bolo 
100% hotovo uz to bol mirror ako ma byt .. teda ze ked sa jeden disk vybral 
druhy siel .. Dalsia bezma prevadzka nemala az 3 hodinove omeskania kym su data 
na oboch diskoch ale kolko to ozaj bolo co milisekundy alebo ... som nezistival 
lebo som skaredo piiip ze natky skpiip sata spiiipraid za tusim 6000 mozem 
piiiip.
c, driver pre linux ... tam sa nemohucost a to ze su to len SATA disky ku 
ktorym sa dava soft ukryty do "drivra" robiaci raid prejavila okato .. No 
predosle ukazky aj zarytym zastancom SATA raidov stacili aby si trhali vlasy.
jadnalo sa raz o ... a raz o nejaky drahsi "sata raid" ale uz typ neviem lebo 
som ho oplul.

PDC20621 [SATA150 SX4] 4 Channel IDE RAID Controller
Vendor 105a: Promise Technology, Inc. ID karty: 6622

btw tieto raidy sa zvyku oznacovat nie winraid ale fakeraid

Promise FastTrak SATA150, SATA150 TX2, SATA150 TX2plus, SATA150 TX4, SATA150
SX4, SATA378, and Ultra 618 series (e.g., PDC20621, PDC20275, PDC20618,
PDC20318, PDC20319, PDC20375, PDC20378, and PDC20376 chips) - libata's
sata_promise driver (for tx2/tx4) or sata_sx4 (for sx4) provides beta-level
support a/o 2004-02-25 (included in kernel 2.6.x). libata drivers don't support
any PATA devices, only SATA. Fakeraid (mitigated by the fact that the Promise
chip (TX4, but not TX2) functions as a "RAID accelerator" - XOR engine and
memory, leaving RAID logic to the host CPU): Proprietary fakeraid "ft" driver
(ataraid?) is available, as are instructions. An now-unmaintained 2003-02 i386
binary driver (often claimed in error to be open source; people being fooled by
its source-code wrapper) is also available.
 I have a Promise SX4 SATA RAID card. Why doesn't Linux support my hardware
RAID?
A. SX4 has extensive "RAID accelerator" features. While not true hardware RAID,
this card has several features which do indeed accelerate RAID support.
Unfortunately, Linux does not support the SX4's special RAID accelerator
features at this time.
For certain configurations, Promise's Linux driver will perform better than the
native Linux SATA driver

bios ale teda dorobil nejake fkcie a tak im jemnejsie zvyknu vraviet RAID 
akcelerator ..
(to aby sa ozaj niekto nezacal sudit za podvod)

a super linka je
http://linux.yyz.us/sata/faq-sata-raid.html

z neho je jasne ze existuju HW radi polia ( o ktore sa nestaras a oni robia
raid online)
exituju sproste disky ...
existuju BIOS SW raid ...  ked defakto raidovanie robi SW ale driver ti dali "v
biose"
a excistuje "raid accelerator" ked to nemas v biose ale tvoj "akoze driver"
robi defakto sw raid ...

a pri sata diskoch sa o HW raid (teda ten ozajstny online ked to nerobi tvoj
procesor)  je to velmi velmi ziradkeve lebo vsetci robia defakto SW raid karty
ale ten SW vopchali (kod) do biosu ale tvoj oper system to vsetko musi spravit
sam ...

Linux sa k tomu stavia ale dost odmietavo lebo kedze to ma robit nas CPU tak ..
to si mozme spravit SW raid bez kamuflaze ... proste cez software ...


Viac viz google..

bbo
----- Original Message ----- 
From: "Matus UHLAR - fantomas" <uhlar na fantomas.sk>

Jan Satko <satko na quanto.nr.sanet.sk> wrote:
> Existuju ale aj HW raidy (tiez PCI karticky), ktore stoja par tisic korun,
> tiez sa Vam zlepia disky do "jedneho".....len cele tie operacie spojene s
> vypoctami raidu...atd....robi Vas procesor na zakladnej doske :-)
> preto sa niekedy oznacuju taketo raidy ako WinRAID (zeby od slova windows
> :-)

Ja by som ich neoznacil ako HW RAIDy ale aho "HW" RAIDy.
dokonca mam pocit ze oznacenie HW RAID je podvod, len sa s nimi musi
niekto zacat sudit...