On 07/19/2011 02:27 PM, Roberto Spadim wrote:
no this not work very fast...
use bcache or other similar ssd+harddisk cache solution (facebook
have one solution i don´t remember the name)
mixing ssd and hdd are a big problem, since write speed is the slowest
(maybe ssd maybe hdd) and read speed isn´t very well since read in ssd
can be non sequencial and at hdd sequencial is prefered, the read
balance algorithm is tuned to use the near position device, and
sometimes ssd isn´t used, or less used or more used...
a bigger speed can be done using a cache solution (ssd+hdd or ssd+raid1(hdd))
that was my test results... maybe someone have others results
You needed to use write-mostly, that would have drastically altered your
results. With write-mostly and write-behind enabled on the hard drives,
all reads go to the SSD instead of the hard drives, and writes complete
as soon as the SSD says it is done and the writes to the hard drives
happen in the background.
2011/7/19 Mike Power<mpower@xxxxxxxxxxxx>:
Is it possible to implement a RAID 1 array using two equal size HDD and one
smaller and faster SSD. The idea being that the resulting RAID would have
the same size of the HDD while picking up the speed benefits of the SSD.
You can do something similar today by just buying two hybrid drives and
putting them in an array. By purchasing a dedicated SSD drive for that
purpose you gain the ability of controlling the size of the SSD portion. I
was hoping the RAID array could use the SSD more as a cache then a redundant
storage.
Mike Power
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
