----- "Richard Neill" <rn214@xxxxxxxxx> escreveu: > Matthew Wakeling wrote: > > > > We're about to purchase a new server to store some of our old > databases, > > and I was wondering if someone could advise me on a RAID card. We > want > > to make a 6-drive SATA RAID array out of 2TB drives, and it will be > RAID > > 5 or 6 because there will be zero write traffic. The priority is > > stuffing as much storage into a small 2U rack as possible, with > > performance less important. We will be running Debian Linux. > > > > People have mentioned Areca as making good RAID controllers. We're > > looking at the "Areca ARC-1220 PCI-Express x8 SATA II" as a > possibility. > > Does anyone have an opinion on whether it is a turkey or a star? > > > > Another possibility is a 3-ware card of some description. > > > > Do you actually need a RAID card at all? It's just another point of > failure: the Linux software raid (mdadm) is pretty good. > > Also, be very wary of RAID5 for an array that size. It is highly > probable that, if one disk has failed, then during the recovery > process, > you may lose a second disk. The unrecoverable error rate on standard > disks is about 1 in 10^14 bits; your disk array is 10^11 bits in > size... > > We got bitten by this.... > > Richard Linux kernel software RAID is fully supported in Debian Lenny, is quite cheap to implement and powerful. I would avoid SATA disks but it's just me. SAS controllers and disks are expensive but worth every penny spent on them. Prefer RAID 1+0 over RAID 5 not only because of the risk of failure of a second disk, but I have 3 cases of performance issues caused by RAID 5. It's said that performance is not the problem but think twice because a good application tends to scale fast to several users. Of course, keep a good continuous backup strategy of your databases and don't trust just the mirroring of disks in a RAID fashion. Flavio Henrique A. Gurgel Consultor -- 4Linux tel. 55-11-2125.4765 fax. 55-11-2125.4777 www.4linux.com.br -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
