How to understand the user scope and meaning of snapshot commercialization

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Snapshot commercialization FAQ

Commercialization time and scope related

What is snapshot commercialization?

The snapshot service, as a data backup method for customers using ECS ​​instances, has been in the free public beta stage since 2011.

In order to provide a better ECS snapshot service experience and optimize the cost of snapshot data storage, we plan to adjust the official charging time for snapshot commercialization. The details are as follows:

The official charging time will be changed from the original scheduled 2017 June 1, 2017 has been postponed to 10:00 am on July 3, 2017. From now until 10:00 am on July 3, 2017, the snapshot service storage fee will continue to be waived, but you can still view the snapshot bill details in the fee center ;

Alibaba Cloud plans to adjust the ECS snapshot charging standard and service process. For details, please see: Alibaba Cloud ECS Snapshot Service Price Adjustment Announcement on July 3, 2017.

Transitional preferential period after snapshot commercialization?

Considering that the snapshot service has become a data backup method for many users on ECS, in order to reduce the possible impact of commercial switching on you, the morning of March 28 to July 3, 2017 10 o'clock is the price discount period for the snapshot service. During this period:

The fee for the snapshot service is waived, but you will still see the bill for the snapshot service in the Billing Center > Consumption Details.

What are the scope of users for snapshot commercialization?

The commercial scope of this snapshot service only includes users of Alibaba Cloud’s official website in China. For users using ECS ​​cloud servers such as the International Station or Japanese Station, the commercialization time will be notified separately, and the snapshot services they are using will not be affected.

OSS prepaid storage package related

If I have activated OSS, will the snapshot be automatically saved to my OSS Bucket? ? Do I need to create a new Bucket to store the snapshot?

It will not be automatically saved to the existing OSS Bucket. The storage location of the snapshot is independent of the OSS Bucket you created, and you do not need to create a new Bucket for the snapshot.

I have purchased an OSS prepaid storage package and are using snapshots and OSS services at the same time. Which product will be deducted first for the storage package?

The current storage package deduction order is based on the product delivery time, so there is no priority deduction rule.

After the snapshot is commercialized, I want to continue using it. Which product do I need to purchase, a cloud disk or an object storage OSS resource package?

If you have previously enabled the snapshot service in the ECS console, there is no need to activate it a second time, or purchase or activate other products. You can continue to create snapshots manually, or use automatic snapshots.

The default is pay-as-you-go mode. You can also choose to purchase a prepaid storage package to optimize your snapshot usage costs. Current snapshot products reuse object storage OSS storage packages, and you can optimize snapshot usage costs by purchasing prepaid storage packages.

Fees related

What is the charging model for snapshot commercialization?

After commercialization, the snapshot service will be charged according to the snapshot capacity. Please refer to the snapshot service fee details (pay-as-you-go).

How to calculate the snapshot fee?

Billing standards: Snapshot fees are billed based on the storage space occupied by the snapshot. If there is no user who has purchased a prepaid storage package, hourly deductions will be made on a pay-as-you-go basis by default. The pay-as-you-go hourly price = monthly price/24 hours/30 days. Please refer to the snapshot service fee details (pay as you go).

For example: If your current snapshot capacity in East China 1 is 1200GiB, under the pay-as-you-go model, the monthly usage cost is 1200GiB * 0.148 yuan/GiB/month = 177.6 yuan, and the cost for the previous hour is 177.6 yuan Yuan/24/30=0.2467 yuan.

If you have purchased a 1TiB prepaid storage package in the East China 1 region, the snapshot capacity within 1TiB will be directly deducted from the storage package, and the capacity exceeding 1TiB (200GiB) will be paid as you go. Deductions are made according to the above calculation method.

The fees in other regions can be calculated according to the above calculation method. The prices of pay-as-you-go and prepaid storage packages in different regions are different. For details, please refer to the snapshot price section of the block storage product price details page.

After the snapshot is charged, will the fee start if the automatic snapshot is not stopped?

Yes. If you do not stop the automatic snapshot policy, the snapshot system will automatically generate snapshots according to the snapshot time point you set previously, and retain these automatic snapshots according to the storage period you set previously.

The snapshot will be billed according to the actual occupied storage capacity, so snapshot fees will be incurred. The default is pay-as-you-go mode, and you can also choose to purchase a prepaid storage package to optimize snapshot usage costs.

How to charge for traffic exceeding the prepaid storage package?

Assume that you have purchased a 100G prepaid storage package and currently have 5 snapshots, each snapshot is 20GiB. If you have purchased a 100GiB prepaid storage package, then when the total snapshot capacity does not exceed 100GiB , the snapshot capacity will be deducted from the storage package. Snapshot capacity exceeding 100GiB will be billed according to the pay-as-you-go model.

Snapshots will be charged. Will the previous snapshots be deleted?

Snapshots that have been backed up before will be billed according to the actual occupied storage capacity, so snapshot fees will be incurred. The default is pay-as-you-go mode, and you can also choose to purchase a prepaid storage package to optimize snapshot usage costs. If you no longer need to use these snapshots, you can choose to delete them before formal charging.

If I don’t want to pay, can I continue to use the previous snapshots?

Yes, but charges will be incurred based on the actual storage capacity occupied by the snapshot. Snapshots are charged based on the actual occupied storage capacity, and will be officially charged starting from 10:00 am on July 3, 2017.

If you do not want to pay, it is recommended that you back up the data in the snapshot by creating a disk with a snapshot before formally charging, and then delete all snapshots to avoid unnecessary charges.

After the snapshot is charged, will the previously created manual snapshots and automatic snapshots be charged?

Yes. Manual snapshots and automatic snapshots are just two ways to create snapshots. The snapshots created will be billed according to the actual occupied storage capacity, so snapshot fees will be incurred.

Stop the snapshot policy before charging for snapshots. Do I need to manually delete historical snapshots? Will my historical snapshots be deleted directly after the formal fee is charged?

If you do not want to pay for snapshots, you need to delete the automatic snapshot policy and manually delete historical snapshots before officially charging.

After snapshot charging, undeleted historical snapshots will be charged according to the actual occupied storage capacity. If the account is in arrears, historical snapshots will be deleted 15 days after the payment is in arrears.

After the snapshot is charged, what impact will the account arrears have on the snapshot?

Once the account is in arrears, the snapshot service will be stopped 24 hours after the payment is in arrears. Snapshots are retained for 15 days from the date of arrears; all snapshots will be released after 15 days.

If the account is in arrears, will the associated snapshots (created disks or mirrors) be deleted after 15 days of arrears?

Won't.

What is the relationship between snapshot service and block storage service in terms of charging?

Snapshot service and block storage are billed separately, and there is no billing relationship between them. The bills between the two are also independent.

Functional capacity related

How is the snapshot capacity calculated? Is it equal to the disk size?

The capacity of a single snapshot is smaller than the disk capacity.

A snapshot is a capture of the entire disk data state at a certain point in time. During the process of creating a snapshot, the capacity of a single snapshot is smaller than the disk capacity by eliminating empty blocks. Alibaba Cloud will identify disk space where data has never been written and mark it as empty blocks without metering to save users' snapshot space. Therefore, as long as the customer does not fill up the disk capacity, the capacity of a single snapshot is less than the disk capacity.

Example: A user has a 40 GiB data disk, and the actual amount of data written in the disk is 20 GiB.

The first snapshot is a full snapshot, because holes will be eliminated during the snapshot creation process, so the snapshot capacity is less than 40GiB.

The second snapshot is an incremental snapshot, and the snapshot capacity is equal to the amount of data changed between the two snapshot time points.

For specific snapshot principles, please refer to the incremental snapshot mechanism.

The accurate definition of "data write operation"

First clarify a concept. For the underlying distributed storage system, "data write operation" "Input operation" not only means business data written by users, but also includes a series of I/O operations such as formatting disks.

After the user gets the disk, it must be formatted before it can be used normally. The essence of formatting is the process of establishing a file system. Before a partition or disk can be used as a file system, it needs to be initialized and the data structure recorded on the disk. This process is called establishing a file system.

Therefore, establishing a file system on the disk means writing data to the disk. Different file systems have different file sizes when formatting. The details are as follows:

Windows system formatting is divided into fast and normal formatting:

Quick formatting Just assign a file system to the partition and rewrite the directory table;

Normal formatting will not only perform the above work, but also scan the partition sector by sector to determine and mark bad sectors;

Therefore, normal formatting operation will fill the empty blocks of the disk, which is equivalent to writing the entire disk. In this case, the size of the first full snapshot will be approximately the disk capacity. The actual space occupied by quick format is relatively small.

Linux system formatting is also the process of establishing a file system. Therefore, when the disk has just been formatted and the user has not written business data, the first snapshot will also have a certain capacity, depending on the different file system formats.

Will deleting files within an ECS instance reduce space usage?

The so-called deletion in the file system only marks the header of the file that needs to be deleted, telling the user that this space can be used, and will not reduce the space occupied by the disk itself.

Why is the snapshot capacity larger than the amount of data seen in the file system?

As mentioned above, file system formatting, file deletion operations, and user data writing behavior will continuously reduce the number of empty blocks on the disk, thereby weakening the effect of eliminating empty blocks during the creation of snapshots. . Therefore, you see that the snapshot capacity is larger than the amount of data represented within the file system. For details, please refer to: Why the file size and the space occupied by the snapshot are inconsistent.

Refer to the snapshot increment instructions. If the intermediate snapshot is deleted, can subsequent snapshots be used?

ECS snapshots support restoring the entire disk data from any snapshot. Therefore, deleting one of the snapshots will not affect the data restored from other incremental snapshots.

Example: Snapshot 1 > Snapshot 2 > Snapshot 3, each snapshot and each disk are updated. When Snapshot 2 is deleted, Snapshot 1 and Snapshot 3 can still be used.

Function related

How to activate the snapshot service?

If you have not used the snapshot service, or you have used the snapshot service through the Open API before, please log in to the ECS Management Console > Snapshot Management page, agree to the relevant service terms and activate the snapshot service. Only then can you use snapshot related functions normally.

If you have already enabled the snapshot service in the ECS management console, you do not need to activate the service again and can use the snapshot service normally without being affected. Snapshots are billed based on capacity, and users can choose whether to use them. If they do not use snapshots, there is no charge.

What is the relationship between snapshots and mirroring?

The current image is a product service packaged based on snapshots. The snapshot has a binding relationship with the image created by the snapshot. Therefore, if you want to delete a snapshot, you need to delete the image associated with it before you can delete the snapshot.

How to delete snapshots and mirrors, and the relationship between snapshots, instances, and mirrors while retaining the associated instances and disks?

Snapshots, mirrors, disks, and instances are currently bound. The function of resetting the system disk and initializing the disk depends on the above binding relationships. In April 2017, Alibaba Cloud has decoupled the binding relationship between "image and instance" and "snapshot and disk".

Used for mirrors that have created instances and can be deleted individually. However, after deletion, business operations that rely on the original mirror data, such as reinitializing disk operations, will no longer be possible;

Used for Snapshots that have been created on the disk can be deleted separately. After deletion, business operations that depend on the data status of the original snapshot, such as reinitializing the disk, will no longer be possible;

is used for snapshots that have created mirrors. After deletion, Previously, the corresponding image needed to be deleted before it could be deleted.

What is the relationship between snapshots, block storage, and OSS object storage?

A snapshot is a data backup of a certain disk at a certain point in time. The snapshot service is an efficient and simple data backup method provided for cloud disks.

Block Storage is a low-latency, durable, and highly reliable data block-level random storage provided by Alibaba Cloud for cloud server ECS. It is usually called a disk, and the system disk on the cloud server. and data disks are block storage products.

Alibaba Cloud Object Storage Service (OSS) is a massive, secure, low-cost, and highly reliable cloud storage service provided by Alibaba Cloud. You can upload and download data in any application, at any time and at any place by calling the API, and you can also simply manage the data through the web console. OSS is suitable for storing any type of files and is suitable for use by various websites, development companies and developers.

So snapshot, block storage, and OSS object storage are three independent products, and each is billed separately without any billing correlation. The bills between the three are also independent.

Currently, in order to optimize customer experience and reduce repeated purchase costs, snapshots and OSS object storage can share OSS prepaid storage packages. The prepaid storage package you purchase in a certain region can be used to deduct both the snapshot capacity and the OSS object storage capacity in that region. You can view the resource usage details of snapshots and OSS object storage in the resource package usage details.

Can multiple snapshot policies be set on a cloud disk?

cannot. Currently, a cloud disk only supports setting an automatic snapshot policy.

After snapshot is officially commercialized, snapshot functions will continue to be enriched to meet the actual business needs of more customers.

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