Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Tue, Apr 3, 2012 at 12:28 PM, Maurits van de Lande <M.vandeLande at vdl-fittings.com> wrote: >>What do the experts think: Should this be sufficient to get the perfomance of a single SATA-Disk without DRBD? > > Probably not, nothing will. Beg to differ. The question was, will DRBD pair of SSDs, when replicated with protocol C, match the performance of a single standalone SATA drive. And at least in terms of throughput, you bet it will. A single SATA drive would sustain 50-60MB/s streaming writes max, and that should _definitely_ be doable with a protocol C replicated pair of SSDs. And latency wise, Lars has already given his view on that which I agree with, so I don't need to rehash. > I'm using drbd in primary/primary mode to host KVM images on a two node cluster. (with drbd8.3.12, drbd8.4.1 has some performance issues) > I have switched to SSD's myself(in raid 5 mode). This improved the VM performance, (I guess because reading data is much faster), but drbd syncer speed did not improve. I even installed a 10G network backbone and used 10G network adapters on the servers. But still syncer speed does not go beyond 110MB/s. Ahem. I'm almost certain you're failing to provide some crucial piece of information here. We have customers on 8.3 happily replicating in excess of 300MB/s. That's on Infiniband hardware, but 10G is also certainly capable of going faster than 110MB/s. Just my €0.02. Florian -- Need help with High Availability? http://www.hastexo.com/now