Well, it seems that my data can be outdated, sorry for that. I've just checked performance numbers on Tom's hardware and it seems that best sad really do 500 MB/s. Some others do 100. So, I'd say one must choose wisely (as always :-) ).
Best regards, Vitalii Tymchyshyn 1 груд. 2012 00:43, "Mark Kirkwood" <mark.kirkw...@catalyst.net.nz> напис. > Hmm - not strictly true as stated: 1 SSD will typically do 500MB/s > sequential read/write. 1 HDD will be lucky to get a 1/3 that. > > We are looking at replacing 4 to 6 disk RAID10 arrays of HDD with a RAID1 > pair of SSD, as they perform about the same for sequential work and vastly > better at random. Plus they only use 2x 2.5" slots (or, ahem 2x PCIe > sockets), so allow smaller form factor servers and save on power and > cooling. > > Cheers > > Mark > > On 30/11/12 23:07, Vitalii Tymchyshyn wrote: > >> Oh, yes. I don't imagine DB server without RAID+BBU :) >> When there is no BBU, SSD can be handy. >> But you know, SSD is worse in linear read/write than HDD. >> >> Best regards, Vitalii Tymchyshyn >> >> >> 2012/11/30 Mark Kirkwood <mark.kirkw...@catalyst.net.nz >> <mailto:mark.kirkwood@**catalyst.net.nz <mark.kirkw...@catalyst.net.nz>>> >> >> Most modern SSD are much faster for fsync type operations than a >> spinning disk - similar performance to spinning disk + writeback >> raid controller + battery. >> >> However as you mention, they are great at random IO too, so Niels, >> it might be worth putting your postgres logs *and* data on the SSDs >> and retesting. >> >> >
