Is there is are some way to setup local replication of the one disk to the another ( Ubuntu ) in the such way that all read operations will be involve only first disk ? Such configuration will be very usefull for AWS SSD instances. In this case SSD instance storage ( which is non-persistent disk and will be erased after instance stopped ) can be replicated to the EBS disk. When using such configuration data intensive services ( like MySQL or MongoDB ) can be configured to use SSD disk and in the same time we can ensure that data will be permanently stored in the EBS.
3 Answers
You can try to create md
device in RAID1 mode where the read operations are issued to the faster device preferably
mdadm --create --verbose /dev/md0 --level=mirror --raid-devices=2 --write-mostly /dev/sdb1 /dev/sdc1
where the device /dev/sdb
is slower for reading (e.g. SATA drive) while the /dev/sdc
is performing better (e.g. SSD drive). The configuration above means the drive /dev/sdc
will be avoided for reading.
What you are looking for is called bcache: http://bcache.evilpiepirate.org/
It writes and reads from the faster device, while periodically writing to the slower one
this might help you:
dd if=/dev/sda of=/dev/sdb
dd command can copy disk in raw format. It will copy partition table and bootloader and all partitions within this disk.
if=/dev/sda : Input disk (source)
of=/dev/sdb : Output disk (destination)