Showing posts with label lvm. Show all posts
Showing posts with label lvm. Show all posts

Thursday, April 24, 2014

AWS Import/Export file limits

AWS import/Export can handle volumes of larger then 1TB to be stored on Amazon EBS volumes. However, there is a intermediate step using S3.  If your storage device’s capacity is less than or equal to the maximum Amazon EBS volume size of 1TB, its contents will be loaded directly into an Amazon EBS snapshot. So, in theory no size limit. AWS does not mount the file system on your storage device, nor is a file system required to be present. AWS Import/Export performs a block for block copy from your device to an Amazon EBS Snapshot. If your storage device’s capacity exceeds 1TB, a device image will be stored within your specified Amazon S3 log bucket. You can then create a RAID of EBS volumes using software such as Logical Volume Manager, and copy the image from Amazon S3 to this new volume

Wednesday, December 4, 2013

MySQL Recover from EBS snapshots for logical volume

In this blog post http://cloudconclave.blogspot.com/2013/12/mysql-ebs-snapshots-for-backing-up.html, we backed up a MySQL database that stores its data across an LVM using multiple EBS volumes.  Now we will do a restore.

sudo /etc/init.d/mysqld stop 
sudo umount /dev/md0 
sudo mdadm --stop /dev/md0 
sudo mdadm --zero-superblock /dev/sdf 
sudo mdadm --zero-superblock /dev/sdg 
aws ec2 detach-volume --volume-id vol-1 aws ec2 detach-volume --volume-id vol-2
aws ec2 create-volume --snapshot-id snap-1 --availability-zone AZ -- volume-type standard
aws ec2 create-volume --snapshot-id snap-2 --availability-zone AZ -- volume-type standard
aws ec2 attach-volume --volume-id vol-New1 --instance-id INSTANCE -- device /dev/sdf
aws ec2 attach-volume --volume-id vol-New2 --instance-id INSTANCE -- device /dev/sdg

Create the stripped volumes:
yes | sudo mdadm \ --create /dev/md0 \ --level 0 \ --metadata=1.1 \ --raid-devices 2 \
/dev/xvdf /dev/xvdg
sudo mount -a sudo /etc/init.d/mysqld start







MySQL : EBS snapshots for backing up a logical volume manager

It is possible to use EBS snapshots to backup a MySQL databases when the data is stored on a logical volume manager.   You have to be make sure all active/cached data is written to disk and no write happens to the data files during the snapshots.

Snapshotting a stripped volume:
Flush data to disk, lock tables, and freeze disk writes:
1. mysql -u root -p password 
(at the MYSQL prompt) 
A. FLUSH TABLES WITH READ LOCK;
B. SHOW MASTER STATUS; 
C. SYSTEM sudo xfs_freeze -f /data
Snapshot all EBS volumes that are part of the logical volume manager:

2. At the Linux prompt:
A. aws ec2 create-snapshot --volume-id vol-xxxxxxxx --description "Snapshot of /dev/sdf" 
B. aws ec2 create-snapshot --volume-id vol-xxxxxxxx --description "Snapshot of /dev/sdg"

Unfreeze disk writes and unlock tables
3. mysql -u root -ppassw-lab awslab
(at the MYSQL prompt) 
A. SYSTEM sudo xfs_freeze -u /data 
B. UNLOCK TABLES;

Wednesday, March 6, 2013

AWS EBS snapshot volumes for MySQL

This community software solution works to ensure MySQL databases deployed on AWS EBS volumes are keep in sync when snapshots are performed.
https://github.com/alestic/ec2-consistent-snapshot, it flushes OS and some application caches to disk before creating EBS snapshots. It works on most *nix, it will also snapshot arrays of EBS volumes.