Talk:Hardware deployed May 9, 2005: Difference between revisions

Revision as of 11:14, 31 March 2005

Revision as of 11:56, 31 March 2005

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Redundant power module for main Cisco switch, PWR675-RPS-N1 or equivalent. This is a key single point of failure for the site and needs protection.

For recovery from major failures, additional backup and log storage on all existing database servers. For master servers, the logs here are the long term binary logs space for which has twice filled the costly and small SCSI drives. The larger SATA drive and a log moving script is expected to reduce the chance of repeats of unexpected master database server switches for this reason. One 400GB SATA drive for five servers, to go in the internal drive bay. This will allow each to have its own local backup with storage for logs holding all changes since the last backup, allowing roll-forward restoration of each server independent of the others. The drive will also improve general performance by being used for temporary table storage during queries. The 3 existing SCSI servers do not have a SATA connector so will need a PATA to SATA adaptor for the drive (all SATA drives to keep all our drives SATA for simplicity). Need to chaek with SM whether the two SATA boxes have the motherboard SATA module or also need PATA to SATA option. Cable length needed is about 24" (about width ofa rackmount case).

For some possible donated equipment and for sites with limited rack slots, also because it appears that dual Xeons will be more cost-effective than a pair of single P4s, want to evaluate one dual Xeon and one dual Opteron 1U box (for reference, Liveournal uses dual Xeons and one major potential hardware donor is also specifying them). Need to test them to see if they deliver and to evaluate in our load balancing setup.

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New primary master database server, with 16GB of RAM, dual Opterons and six 140GB 15,000 RPM SCSI drives in RAID 0, delivering 420GB of usable space. Caching SCSI controller. 400GB SATA drive in internal bay and motherboard SATA controller added. This will partly evaluate the usefullness of 16GB of RAM. ''Once this is proved in service, Ariel is planned to be switched to RAID 0 to give it 400GB of usable disk space.''

En/ja Wikipedia search/general database slave. For en Wikipedia with Mediawiki 1.4, 4GB is no longer sufficient to cache the amount of data in cur and the search indexes. To provide additional search capability and to evaluate performance with 8GB, a dual Opteron box identical to Holbach but with 8GB of RAM instead of 4GB. SATA has proved generally comparable to SCSI except under high replication load and the en/ja set of database servers is expected to see comparatively high repliation write loads, so SCSI drives are better than SATA for this set. No need for RAID 10 for this slave-only system. Should evaluate 140GB 10K SCSI drives to see if this might be best purchased with 800GB usable space to be part of the terrabyte-usabelusable capacity target for our next generation of servers. 400GB SATA drive in internal bay and motherboard SATA controller added. The Seagate 400GB drive for the internal bay is SM part 12284 $409 and onboard SATA controller for the motherboard is part number 11337 for $42. Have to ask for a specific quote for this internal bay - can't configure it via the site.

De Wikipedia is now an uncomfortably high load for Webster, again for the temporary RAM capacity reasons with Mediawiki 1.4. Same specificaton as en/ja.

Albert is disk speed limited and site performance has been suffering because of it. As a possibly temporary expedient to address this, a new box with dual Opterons, 6x400GB SATA drives in RAID 010 with a wrtiewrite caching SATA controller and 8GB of system RAM for caching. If changes to file handling make this system innecessaryunnecessary it can be switched to database service. Consider 400GB SATA drive in internal bay for temporary file storage while preparing database and image dumps, off the main drives to reduce load on them using non-redundant scratch storage.

==Power failure note==

Both disk conrollercontroller vendors have now addressed the write caching problems which conributed to our (and LJ) power loss trouble. The SATA vendor now has a new driver and the SCSI vendor a new utility to turn off hard drive write caching, with more work planned. For this reason, no switch of controller vendor is planned for this batch of database servers.