Catalyst provides several tiers of storage to suit the varying needs of our customers. All data regardless of the storage tier is replicated on three different storage nodes on the same region.
The standard tier combines SSDs with spinning drives to provide a good
balance between performance and cost. Writes are always done to SSDs first and
then flushed to HDDs later behind the scenes. Reads are likely to be cached by
the aggregate memory of all our storage nodes combined, but will hit a HDD when
the data is not cached.
Due to the performance overheads imposed by the use of spinning drives the IOPS
limits are limited to choices of 100, 250 or 500 IOPS. If a higher IO
throughput is required then you will need to take a look at the performance
tier.
Data stored on the standard storage tier is replicated on three
different storage nodes on the same region.
| Storage type | Replication domain | Replicas | Disk | IOPS [1] |
|---|---|---|---|---|
| b1.standard | Single region | 3 | HDDs and SSDs | 500 |
| b1.sr-r2-hdd-100 [2] | Single region | 2 | HDDs and SSDs | 100 |
| b1.sr-r3-hdd-250 | Single region | 3 | HDDs and SSDs | 250 |
| b1.sr-r3-hdd-500 | Single region | 3 | HDDs and SSDs | 500 |
[1] Please note that the IOPS described on the table above are not guaranteed or provisioned IOPS, but rather the burst limit (ceiling) that each volume can reach from time to time.
[2] The storage type b1.sr-r2-hdd-100 is not recommended for production use. It is designed for development, test and ephemeral workloads
The performance tier makes sole use of direct NVMe SSD drive access for
both read and write operations. This tier offers three options for IO
throughput, which provide a burstable limit of 1000, 2500 and 5000 IOPS.
All options in this tier provide 3 replicas in a single region.
| Storage type | Replication domain | Replicas | Disk | IOPS [1] |
|---|---|---|---|---|
| b1.sr-r3-nvme-1000 | Single region | 3 | NVMe | 1000 |
| b1.sr-r3-nvme-2000 | Single region | 3 | NVMe | 2000 |
| b1.sr-r3-nvme-5000 | Single region | 3 | NVMe | 5000 |
[1] Please note that the IOPS described on the table above are not guaranteed or provisioned IOPS, but rather the burst limit (ceiling) that each volume can reach from time to time.
If you are interested in moving data from a volume in the standard tier to an NVMe volume please checkout How to migrate between HDD and NVMe disks
If you want to launch an instance using an NVMe root volume check out Launching an instance from an NVMe volume for more information.
The root volume of your compute instance should only be used for operating
system data. We recommend you add additional volumes to your compute
instances to persist application data. For example: when running a MySQL
database, you should add at least one additional volume with enough space to
hold your database and mount it on /var/lib/mysql.
While block volumes can be formatted and used independently, we highly recommend you use a logical volume management layer, such as LVM, in production environments. By using LVM you will be able to add additional volumes and resize file-systems without downtime. Please consult the documentation of your operating system for information on how to use LVM.
If you are using volumes independently (without LVM, in a development scenario), then you must label your partitions to ensure they will be mounted correctly. The order of the devices (sdb, sdc, etc) may change and, when unlabelled, may result in them being mounted incorrectly.