One more reason I can't wait for ZFS to become available as lustre's underlying filesystem :)
On Jan 23, 2010, at 11:47 PM, Scott Adametz wrote: > Any possibility to redirect Lustre's OSS Cache or portions of the Linux > pagecache to a location other than RAM such as to an internal SSD (perhaps > even two in RAID0). I ask because the servers we have available (read: > second hand servers) for OSSs physically max out at 8GB RAM. > > The wiki states: "It uses a regular Linux pagecache to store the data." I > looked into pagecache and pdflush tunables but found little on directing the > actual location of the cached content as it tends to focus heavily on tuning > timing of writes-to-disk vs reads. Yes, I understand the absurdity of > trying to redirect RAM cached content back to "disk" but with rapidly > evolving SSD design and performance it actually makes some sense in this case > for Lustre cache data. Obviously I would prefer to redirect only Lustre OSS > cache data and not the entire Operating System page cache. > > While an SSD is nowhere near as quick as RAM, it would still seem beneficial > to have more frequently viewed content available for reads even from an SSD > vs a spinning disk, especially with our use case (HD video editing and > playback). Until SSD prices come down to reasonable levels and we can afford > to replace all spinning disks with SSDs, any little bit helps ;-) > > In sum: just a thought to be able to designate, in Lustre configs, an > additional low-latency "swap" or "cache" location on the OSSs. Adding one > SSD to each OSS sure beats having to buy new servers with more RAM capacity > or using all SSD drives and blowing the budget... > > Thanks for the time, > > Scott Adametz > Systems Engineer > Big Ten Network > FOX Networks Group > [email protected] _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss
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