High availability tips & ideas

[George Daflidis-Kotsis]

On Wed, Feb 19, 2003 at 10:02:55AM +0200, Georgatos Vaggelis wrote:

> OOOOOOOOOOOOOOOOOOPpppppppp!!!!!!!!!!!!!
> 
> paidia exoume pelagodromisei -- ews mple3ei ta UTP kalwdia mas --...
> 
> Allo to clustering allo to fail over, kati pou kanei katapliktika to HA.
> To HA DEN einai clustering software apla sthn periptwsh pou skash kati
> sthn mia mhxanh me ena arp spoofing klp 8a sikosei MIA (mono dyo mporoun
> na symetexoun) allh gia na kanei thn doulia apo ekei kai pera. Sto
> clustering apo thn allh yparxei enas DIRECTOR, dhladh enas software
> agent pou se M$ perivalonta trexei sto ena apo ta dyo melh tou cluster.
> Kanonika prepei na trexei (apodotikotero or8otero klp) se mia trhth
> mhxanh opote exeis to sxhma ginetai ws e3is:
> 
> exeis ena director pou 3erei ti kanei o ka8e server (status, load I/O
> wait klp) kai ta requests pou tou erxontai (stnh periptwsh mas ftp
> downl) o client den 3erei POTE amesa (kai den ton endiaferei) me poion
> server mhlaei afto stelnei ta request sto Virtual IP to opoio to krataei
> o director kai synalasetai me afton, ara AN symbei kati KAKO se ena apo
> tous x servers pou kanei serve to en logo request tote DIAFANWS gia to
> XRHSTH, ante na dei ena mhkro drop sthn taxhthta an kai gia afto
> yparxoun ta buffers, 8a kanei o director re-establish to conection me
> ena allo server kai 8a synexisei.
> 
> gia perisotera peri clustering se afto to epipedo rikste mia matia sto
> http://www.LinuxVirtualServer.org pou exei kai polly orea docs .

Mporei kapoia solutions na akolou8oun to parapanw sxhma, alla den
isxuei gia oles tis periptwseis. Kai sto clustering den einai aparaithto
na exeis ena director klp.

Filika.

-- 
[george daflidis-kotsis - systems admin,web/e-commerce - gdk at demon.net]