That actually sounds like an awesome idea! memcached is great but having persistence would give a whole new quality!
Storing sessions or whatever state you need would be much more reliable. Space available would grow 10 fold as well :- ) Great idea, would love to see it as an option in production stable memcached ! art On 14 July 2010 06:42, Mitch <gmi...@gmail.com> wrote: > Hi Marten! > > I have developed a patch for memcached 1.4.x that splits memcached's > slab store into metadata and data bits, so that the key/values can > live on flash without a tremendous performance penalty. Ultimately, I > predict the best solution will be to use the storage engine branch and/ > or Northscale's membase, but for the time being the patch works pretty > well. I'll send you a private email with more info. > > thanks! > Mitch (from Fusion-io) > > On Jul 9, 10:01 am, Marten Lehmann <coolcoyo...@googlemail.com> wrote: > > Hello, > > > > I know that memcached is designed to get its speed from the fast > > access to RAM. But RAM is still very expensive - even with the amount > > of RAM you get for the same money increasing every year. > > > > When I thought of using PCIe SSDs instead of RAM I wasn't doing this > > with regard to persistence of objects. I just noticed, that the Fusion- > > io's ioDrives are working with near-RAM speed, having the PCIe bus as > > the only bottleneck in speed (don't mix it up with SATA SSDs). An > > ioDrive 160 GB with SLC memory is available for less than $6,000 and > > is capable to perform more than 100,000 random IOPS (read and write), > > whereas with ECC RAM you'd have to pay a multiple of that amount the > > get the same ressources. > > > > I don't know of any way to use a block device (like the ioDrive) as > > RAM, you can only use RAM as a block device (which doesn't help in > > this situation). So for the emerging market of PCIe SSDs (many high > > performance databases are using this as replacement for RAID 10 arrays > > and large RAM) it would be necessary to extend or branch memcached to > > support SSD block devices. > > > > Did someone start with that, is this possibly already on the roadmap, > > or did the maintainers refuse to extend memcache with this option for > > a reason? > > > > Btw.: We are using memcached in conjunction with nginx as a web proxy > > to our backend webservers to cache images and other static files, > > which improves performance a lot. But 64 GB of RAM is much more > > expensiv than 160 GB of an ioDrive PCIe SSD. > > > > Kind regards > > Marten
