I am using an r4.4xlarge instance which has a maximum IOPS limit of 18750 (Referred from docs here, and I have attached an io1 volume with 20,000 IOPS on it.
My question is, will it be a waste of 1250 IOPS? Will the instance cap the max IOPS earlier than the volume's IOPS limit reach?
Related
Assuming I have a gp3 SSD backed EBS with 3000 IOPS with block size of 256kb & througput of 128Mbps ( EBS is not optimized )
What happens to my IO requests if I exceed the 3000 IOPS request? Do they stall? Or is that more of a function of throughput?
Let's take an example
An application does 3000 random IO (so no chance of merging) of 1kb size per second. This means I will be hitting the IOPS limit but throughput is only 3Mbps. Will this cause my further IO operations to stall?
Is it preferable to increase my IO size in that case?
EBS will throttle your I/O in this case and you will not see more than 3000 IOPS. In general, they have throttling at EBS volume level and at EC2 instance level (max/baseline EBS IOPS of EC2 instance type, limit across all attached EBS volumes). You will be throttled as soon as you hit any of those limits.
Why should one uses IO1 volume over GP3 when it is now possible to manually enter the number of IOPS desired for the GP3 volume ?
It always depends on what your workload needs. The documentation has a nice comparison chart: EBS Volume Types: Solid state drives (SSD)
The main differences are the following:
gp3 can scale up to 16.000 IOPS whereas io1 can scale up to 64.000 IOPS
io1 volumes support EBS Multi-Attach and gp3 doesn't
If you need EBS Multi-Attach or more than 16k IOPS, you'll probably want to go with io1 volumes, otherwise gp3 will usually be fine.
Just creating a couple new small volumes for a new SQL server's TempDB files. So I only need 2 20GB volumes but noiticed on pricing that:
General Purpose (SSD) - 500GB - 1500 / 3000IOPS = $51.70
Provisioned
IOPS (SSD) - 20GB - 1500 IOPS = $110.76
But something is telling me deep down that Provisioned IOPS must surely offer something more such as a guarentee yet general purpose gives you IOPS in the range of 1500 but based on how much strain the rest of the volumes are under? Else what's the point in using the smaller volume with provisioned IOPS?
Regards
Liam
For some applications, "predictable performance" is more important than "high performance", and PIOPS gives you both. One should always test, but for the case case you described, GP2 SSD really seems more efficient.
You can get even more out of GP2 combining volumes using RAID/LVM. For example, 1 1TB => 3K IOPS max, 2 x 500 GB => 6K IOPS max...
From the aws ec2 CALCULATOR(http://calculator.s3.amazonaws.com/index.html):
General purpose ssd
1000G storage,
3000 IOPS,
$97/month
Provisioned IOPS ssd
1000G storage,
3000 IOPS,
$320/month
My questions
If I attach 1000G General ssd to a ec2 instance, and used 100G, what IOPS I really get? 3000 or 300?
If question1 is 3000, in what conditions we should use provisioned IOPS ssd, while we can increase IOPS by adding storage at lower cost?
The baseline performance is 3 IOPS per GB of storage and can burst up to 3000 IOPS per volume. However the burst probably wont come into play. Since baseline for 1000GB volume is 3000 IOPS.
When you need more than 3000 IOPS. With provisioned you can get up to 30 IOPS per GB.
The instance size you attach these volumes to will also affect performance.
We have a replication setup on Amazon EC2 that used Magnetic disks (15GB) that we swapped with SSD disks (15GB) for each the replication servers. We noticed that the slaves would fall behind the master and never catch up with these new SSD disks. This is something that never happened with the Magnetic disks but happened on each and every SSD disk.
We decided to try and move the databases back to Magnetic disks after the SSD disks fell more than 2 days behind. Within 2 hours the slave completely caught up.
I thought that SSD disks were more efficient, and all around better than Magnetic disks and that is why Amazon decided to make them standard.
Another bit of information is that we are using Micro instances, but the only changes we made was with the attached disk.
Anyone have any ideas?
I think you might be bumping up against the max IOPS for your 15GB SSD drive.. Amazon only allows an average of 45 IOPS for that disk size. On a magnetic drive, they have an extra charge when you use more IOPS, it does not seem to be throttled in the same way:
From Amazon's Pop Up on IOPS:
The number of input-output operations per second. For Provisioned IOPS (SSD) volumes, you can specify the IOPS rate when you create the volume. The ratio of IOPS provisioned and the volume size requested can be a maximum of 30 (in other words, a volume with 3000 IOPS must be at least 100 GB). General Purpose (SSD) volume types have a baseline IOPS of volume size X 3 and can burst up to 3000 IOPS for 30 minutes.