Hi, > -----Original Message----- > From: Manuel Dur�n Aguete [mailto:[EMAIL PROTECTED]] > Sent: Mittwoch, 30. Januar 2002 14:29 > To: [EMAIL PROTECTED] > Subject: A Few Questions > > > Hi, > > I'm building my first database sever with sapdb for a degree > project in data > capturing and postprocessing and I'm not sure about this questions: > * Can I use a scsi controller with cache without data > loss? If I can > must configure it to cache only read isn't it?
A good question. To make absolutely sure, that you do not lose any commited transaction at least your LOG Devspaces must work this way. If your SCSI controller looses its cache content during powerfail, you could otherwise loose LOG information of the last completed transactions. I am not sure, that SCSI controller manufacturer are willing to confirm that they cannot loose data. We are always writing 'SYNCED' on disk, but the SCSI driver writers not always think about disabling caching, since it dramatically reduces drive speed. If you do not sign a contract with somebody, that all your committed transaction are 'save', you are on the good side if you buy a powerfull enaugh UPS and use an operating system that reacts correctly on powerfails. I you strive for perfection you should buy a SAN solution like EMC and switch of any cache on your controller. > * What type of SANS network storage device can I use, if > I can ? I think > that I'cant use none, but I need and answer to justify this. You can use whatever you can effort. SAN solutions normally are transparent. NAS solutions may need special mount options, to ignore file locking requests (some problem with using NFS mounts...). > * Is there any binary version of SAPDB for ia64 running > linux-ia64 There is an inhouse port, which is not published yet. > * Can I use linux raw devices for devspaces? Its a little bit depend on your LINUX version, but it is possible with the right LINUX patches. > * It's there any product for online replication of database (SGDB > master -> SGBD slave), like mysql's one ? not yet, but it is planned and has at least already a name: Replication Manager > * It's there a tool or command like VACUUM in Postgresql or isn't > neccessary? I don't know VACUUM. > * With computer it's most suitable for about 2Gb db > data/month with > tipical operation SELECT, INSERTS, JOIN, DELETE,etc ... I've > thinking about > an Itanium/Xeon with a lot of memory and disks. The next years machine... Itanium currently available must be replaced by Kimberly before you should think about buing it. Xeons restrict you to 32Bit address space, which is not very much for a big machine... > * Could somebody explain me the different types of databases > DW,LiveCache,etc... SAPDB has one executable, that is configured for special purposes. LIVECACHE is used to setup SAPDB primarily as Memory Database with ability to store persisitent Objects. DW (Datawarehouse) is used primarily for data mining. CS (ContentServer) is used if database is setup for documentation storage. OLTP (OnlineTransaciotnProcessing) is used for 'normal' SQL business. Each instance configures a special set of parameters, i.e. Only Livecache instances allow OMS_REGIONS, setup more strictive request-timeouts, setup garbage collectors, setup different stack size etc. > _______________________________________________ > sapdb.general mailing list > [EMAIL PROTECTED] > http://listserv.sap.com/mailman/listinfo/sapdb.general > _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general
