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56

An AMI is, as you note, a machine image. It's a total snapshot of a system stored as an image that can be launched as an instance. We'll get back to AMI's in a second. Lets look at EBS. Your other two items are sub-items of this. EBS is a virtual block device. You can think of it as a hard drive, although it's really a bunch of software magic to link into ...


23

Like others have said, EBS--Elastic Block Storage. I am using it myself now that it is released to the general public. It is better than S3 on multiple points: EBS are fast. Faster than even the local mounts, according to Amazon. EBS mounts as proper devices. Unlike S3, which you'll need custom S3 oject access logic in your code, or middleware ...


20

I had the same question as you, so I worked out how to do it. First, I did this from the Ubuntu 32-bit EBS-backed ami from the US-East region, other OS's or images may work differently. However, I suspect that you should be ok, as long as you are using an ext* filesystem. It might work on other filesystems, but you'll have to figure out how to resize them ...


17

When you attach an EBS volume, you specify the device to attach it as. Under linux, these devices are /dev/xvd* - and are symlinked to /dev/sd* In the AWS console, you can see your EBS volumes, what instances they are attached to, and the device each volume is attached as: You can achieve the same thing from the CLI tools. Set the necessary environment ...


15

You're safe to use the volume once you have triggered the snapshot, even if it's still in a pending state according to AWS - see this post. If you're taking a snapshot for the first time, it probably will take a while as it has to make a full copy to the region-wide S3 bucket, but remember, it's incremental after the first one has been stored so should be a ...


14

Yes, EBS is fault tolerant on the back end, but EBS failures do occur and in unexpected ways. What you don't see is the type of failure that most of us are used to - drive goes bad and just fails outright. The most frequent failure is a huge and unpredictable increase in latency which can make your application unresponsive. With RAID1 or RAID 10 sets, you ...


13

It would help if you posted your my.cnf and whether you are using InnoDB or MyISAM tables and whether you are a read-heavy or write-heavy workload. Otherwise, we are just making guesses. Here are mine: First, I would look and make sure that your queries are properly indexed. High I/O on MySQL databases is either caused by extremely high concurrency, a ...


13

If the root file system is ext3 or ext4, then run: sudo resize2fs /dev/xvda1 If the root file system is xfs (less common), then run: sudo xfs_growfs / You can omit "sudo" if you are logged in as root. These commands should be run while the system is running and the file system is mounted. It's standard for EBS volumes to not contain a partition ...


10

On a default UNIX-like system, cron has a minimal environment defined. Usually HOME, SHELL, LOGNAME are defined and PATH is set to /bin. You have two solutions: enter the full path of your script. ie: /home/me/bin/ec2-automate-backup.sh alter the PATH environment variable. If you want to receive email from the cron daemon define the MAILTO variable. ...


10

As you said, this isn't exactly an apples to apples comparison (in addition there is agreement already, that decent data backup procedures must be in place for both, so I'm not going to address this). Therefore the question cannot be answered as such, rather one should be aware of the architectural details of each offering and apply those in respect to a ...


10

Here's a complete set of commands that you should run once you've attached the EBS volume to your EC2 instance: mkfs -t ext3 /dev/sdf # (NOTE - if you created your EBS volume from a snapshot of another volume and want to preserve its data, skip this step) echo "/dev/sdf /testName ext3 noatime 0 0" >> /etc/fstab mkdir /testName mount /testName ...


9

Just to add a little to the consensus that is EBS faster... An important point to understand here is that instance storage speed is unpredictable - Amazon makes no guarantees about it. This information comes from the book Cloud Application Architectures by George Reese (which seems pretty good from what I've skimmed it so far.) It includes a table titled ...


9

EBS is charged hourly and it's against what you allocate. The snapshots are supposed to only be what you've used within the allocation. For 100GB it'll get rounded up to a whole hour's usage and assuming the East or West region you should warn your bank about the incoming charge of about $0.02.


8

What does it provide? Quite a lot, if you're not a DBA. Automated snapshots to the second for the previous five minutes (configurable up to 8 days) DB snapshots are automatically scheduled, managed, and stored HA without having to think about it? Sign me up! As for your additional questions; the RDS DB is persistant, and it's equivalent to setting up ...


8

Make sure the EBS-drive has the name /dev/sda1 in the EC2-Console.


8

One thing to remember is that not all data needs to be permanent. Instance store provides a cost effective solution for dealing with temporary data. Let me provide a few examples. The most obvious is swap space. If you want to allocate a few GB of swap space, a file on an instance store device is perfect - no cost to the I/O operations, and the data does ...


7

Amazon has not provided a simple command line interface to copy EBS boot AMIs between regions like they did with S3 based AMIs. In order to copy an EBS boot AMI, you need to start instances in both regions and copy the EBS snapshot from one region to the other using a temporary EBS volume attached to each instance. I recommend using rsync with appropriate ...


7

There's nothing broken, so there's not really anything to "fix". This change (/dev/sdX to /dev/xvdX) was made in recent kernel versions (perhaps the 3.x tree? I can't recall specifically at the moment). EC2 hasn't yet changed their terminology to reflect the change in device naming conventions, as that would confuse all those who are running older kernels. ...


7

It all depends on how much you want the data gone. If you just want to avoid having to sit through a lengthy rm, then a reformat (as suggested by Sysadmin1138) would do the trick. If you'd prefer not to have to worry (too much) about the data still being accessable, then being an EBS volume you can just unattach it and attach a new one, and let Amazon ...


7

Amazon does not recommend RAID1 (which is part of RAID10). See "Amazon EBS Volume Durability" in http://aws.amazon.com/ebs/ where they state: "Because Amazon EBS servers are replicated within a single Availability Zone, mirroring data across multiple Amazon EBS volumes in the same Availability Zone will not significantly improve volume durability." ...


7

Your approach sounds very good - but I can think of a possible way to improve it. To reduce the impact of data loss since the last backup, and EBS volume failure (unlikely, but still possible) you could store your data on a separate EBS volume than your system files, and back up the data volume more frequently than the system volume. With your current ...


7

The EC2 monitoring documentation suggests a method of doing this by installing the Monitoring Scripts for Amazon EC2 Instances and then configuring a cron job to gather the data and reprt back.


6

Actually, your best bet is probably the Amazon Linux AMI: http://aws.amazon.com/amazon-linux-ami/ It's CentOS/RHEL under the hood, so you can use all the CentOS RPMs and such, but you get Amazon's tweaks and improvements so it runs even better in EC2.


6

The CPU can and will be used for other processes, provided there is at least one process that is ready to receive CPU time. There's the rub - you can have an I/O-bound system with every process waiting for I/O to complete, and as there is nothing waiting for CPU time, there is no reason to schedule (and utilize) CPU for anything other than the kernel's ...


6

While all instances, other than the t1.micro, do have an allocation of 'instance storage' (i.e. ephemeral storage), that storage is not necessarily attached by default. In most cases, instances with an EBS root volume will have zero or one attached ephemeral volumes. The ephemeral disks, available to an instance are labelled ephemeral[0-3]. You can NOT ...


6

You can change the instance type of an existing instance without the need to duplicate and create a new instance. From the AWS Management Console: Stop your instance From the menu, select "Change Instance Type" to change your instance to a more powerful type Start your instance Do your work and revert when done.


6

The volume is 100GB, but the filesystem is still only 10GB. You need to grow/expand the filesystem to fill the rest of the space on the disk volume. The method you use to do this depends on what type of filesystem you're running on this volume. If you're running an ext3 filesystem, it's as simple as: $ resize2fs /dev/xvdX (replace xvdX with the correct ...


6

Performance of EBS volumes can be affected by things like: New EBS volumes have a first-use penalty, even if they are created from an EBS snapshot. The first time you read or write to each block on the volume will take much longer than subsequent hits. When an EBS snapshot has been initiated, the EBS volume may experience high iowait when you try to write ...


6

Amazon does not currently provide a method to report on the storage used by snapshots other than the total usage and cost numbers for all snapshots in the account. Snapshots of the same or related volumes can share storage (where blocks have not changed between snapshots) so this makes it difficult to define the size of a single snapshot. A new snapshot ...


6

I was able to resolve the issue in the following way: umount [the mountpoint] mount /dev/data_vg/data_lv -o inode64 [the mountpoint] Apparently, the default (32-bit inodes?) xfs will store all inodes in the first 1TB portion of the disk. This means that if the first 1TB is full, then you'll run into no space on disk errors even if it appears you have ...



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