On Dec 12, 2012, at 6:02 AM, Craig Ringer <cr...@2ndquadrant.com> wrote:
> On 12/12/2012 09:44 AM, Evgeny Shishkin wrote: >> So far, more than a year already, i bought consumer ssds with 300-400$ hw >> raid. Cost effective and fast, may be not very safe, but so far so good. All >> data protection measures from postgresql are on, of course. > > You're aware that many low end SSDs lie to the RAID controller about having > written data, right? Even if the RAID controller sends a flush command, the > SSD might cache the write in non-durable cache. If you're using such SSDs and > you lose power, data corruption is extremely likely, because your SSDs are > essentially ignoring fsync. > > Your RAID controller's BBU won't save you, because once the disks tell the > RAID controller the data has hit durable storage, the RAID controller feels > free to flush it from its battery backed cache. If the disks are lying... > > The only solid way to find out if this is an issue with your SSDs is to do > plug-pull testing and find out. > Yes, i am aware of this issue. Never experienced this neither on intel 520, no ocz vertex 3. Have you heard of them on this list? > -- > Craig Ringer http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Training & Services
