FAQ about Yandex StoreDoc

General questionsGeneral questions

• What is Yandex StoreDoc?

• What is Yandex StoreDoc's share of database management and maintenance work?

• Not sure when to use Yandex StoreDoc or VMs with databases?

• What is a database host and database cluster?

• How do I get started with Yandex StoreDoc?

• How many database hosts can there be in one cluster?

• How can I access a running DB host?

• How many clusters can I create within a single cloud?

• How are DB clusters maintained?

• Which Yandex StoreDoc version does Yandex StoreDoc use?

• What happens when a new DBMS version is released?

• What happens when a DBMS version becomes deprecated?

• How do you calculate usage cost for a database host?

• How can I change the computing resources and storage size for a database cluster?

• Is database host backup enabled by default?

• When are backups performed? Is a database cluster available during a backup?

• Can I change the retention period of automatic backups?

• What metrics and processes can be tracked using monitoring?

• How do I set up an alert that triggers as soon as a certain percentage of disk space has been used up?

Questions about Yandex StoreDocQuestions about Yandex StoreDoc

• Why should I use Yandex StoreDoc in Yandex StoreDoc rather than my own VM-based installation?

• What happens to a cluster if one of its hosts fails?

• Can I deploy a Yandex StoreDoc cluster in multiple availability zones?

• What is the backup procedure for Yandex StoreDoc clusters?

• How does replication work for Yandex StoreDoc?

• What limitations are there for Yandex StoreDoc clusters?

• Why is the cluster slow even though the computing resources are not used up?

• How do I get access to the local.oplog.rs service collection?

• Can I connect to cluster hosts via SSH or get superuser permissions on hosts?

• What should I do if I get the revocation check error when using PowerShell to obtain an SSL certificate?

General questionsGeneral questions

What is Yandex StoreDoc?What is Yandex StoreDoc?

Yandex StoreDoc is a solution that helps you create, operate, and scale Yandex StoreDoc databases in the cloud.

With Yandex StoreDoc, you can:

• Create a database with the performance specs tailored to your needs.
• Scale processing power and storage dedicated for your databases.
• Get database logs.

Yandex StoreDoc takes over time-consuming administrative tasks in Yandex StoreDoc:

• Monitors resource usage.
• Automatically creates DB backups.
• Provides fault tolerance through automatic failover to backup replicas.
• Keeps your DBMS software up to date.

You work with a Yandex StoreDoc database cluster just like with your regular local database. Thus, you can manage internal database settings to meet your application requirements.

What is the role of Yandex StoreDoc in database management and maintenance?What is the role of Yandex StoreDoc in database management and maintenance?

When you create clusters, Yandex StoreDoc allocates resources, installs the DBMS, and creates databases.

For all created and running databases, Yandex StoreDoc automatically creates backups as well as applies DBMS patches and updates.

Yandex StoreDoc also provides data replication between database hosts (both inside and between availability zones) and automatically switches the load over to a backup replica in the event of a failure.

Be mindful of what is managed by the service and what, by the Yandex Cloud customer. Understanding these areas of management helps you use your cloud resources efficiently and avoid potential database-related issues. For more information, see Zones of control between managed database (MDB) service users and Yandex Cloud.

Not sure whether to use Yandex StoreDoc or VMs with databases?Not sure whether to use Yandex StoreDoc or VMs with databases?

Yandex Cloud offers two ways to work with databases:

• With Yandex StoreDoc, you can use template databases, with no administrative effort required.
• Yandex Compute Cloud virtual machines allow you to create and configure your own databases. This approach allows you to use any database management systems, access databases over SSH, and so on.

What is a database host and database cluster?What is a database host and database cluster?

A database host is a cloud-based isolated database environment with dedicated computing resources and reserved storage capacity.

A database cluster consists of one or more database hosts with configurable replication between them.

How do I get started with Yandex StoreDoc?How do I get started with Yandex StoreDoc?

Yandex StoreDoc is available to all registered Yandex Cloud users.

Before creating a database cluster in Yandex StoreDoc, you need to decide on its configuration:

• Host class that will determine your computing power, i.e., vCPUs, RAM, and more.
• Disk type and size (reserved in full when creating a cluster).
• Network for your cluster.
• Number of hosts for the cluster and the availability zone for each of them.

Learn more in Getting started with Yandex StoreDoc.

How many database hosts can there be in a cluster?How many database hosts can there be in a cluster?

The minimum number of hosts in a cluster depends on the following:

• Selected platform and host class.
• Selected disk type.

The maximum number of hosts in a cluster is only limited by the requested computing resources and the size of the storage for the cluster.

For more information, see Quotas and limits.

How can I access a running database host?How can I access a running database host?

You can connect to Yandex StoreDoc databases using conventional DBMS methods.

Learn more about connecting to clusters in this guide.

How many clusters can I create within a single cloud?How many clusters can I create within a single cloud?

To learn more about MDB technical and organizational limitations, see Quotas and limits.

How are database clusters maintained?How are database clusters maintained?

Maintenance in Yandex StoreDoc includes:

• Automatic installation of DBMS updates and patches for database hosts (including for stopped clusters).
• Changes in the host class and storage size.
• Other Yandex StoreDoc maintenance activities.

For more information, see Maintenance.

Which Yandex StoreDoc version does Yandex StoreDoc use?Which Yandex StoreDoc version does Yandex StoreDoc use?

Yandex StoreDoc supports Yandex StoreDoc versions 6.0 and 7.0.

What happens when a new DBMS version is released?What happens when a new DBMS version is released?

When new minor versions are released, the cluster software is updated after a short testing period. Owners of the affected DB clusters are notified of expected work times and DB availability in advance.

What happens when a DBMS version becomes deprecated?What happens when a DBMS version becomes deprecated?

One month after the database version becomes deprecated, Yandex StoreDoc automatically sends email notifications to the owners of DB clusters created with this version.

For clusters with a deprecated DBMS version, there is no option to create new hosts or restore from backups. Database clusters are automatically upgraded to the next supported version seven days after notification for minor versions and one month after notification for major versions. Deprecated major versions are going to be upgraded even if you have disabled automatic updates.

How do you calculate usage cost for a database host?How do you calculate usage cost for a database host?

In Yandex StoreDoc, the usage cost is calculated based on the following:

• Selected host class.
• Reserved storage capacity for the database host.
• Size of database cluster backups. You do not pay for backups as long as their size does not exceed the storage capacity. Additional backup storage is charged according to our pricing policy.
• Database host uptime in hours. Partial hours are rounded to the nearest whole hour. For the cost per hour of operation for each host class, see our pricing policy.

How can I change the computing resources and storage size for a database cluster?How can I change the computing resources and storage size for a database cluster?

You can scale your computing resources and storage size directly in the management console by selecting a different host class for your cluster.

The cluster settings will update within 30 minutes. This window may also be used for other maintenance tasks, such as installing updates.

Are database host backups enabled by default?Are database host backups enabled by default?

Yes, backups are enabled by default. For Yandex StoreDoc, a full backup is performed once a day with the possibility to restore it to any saved backup.

By default, backups are stored for seven days.

When does a backup run? Is a database cluster available during backups?When does a backup run? Is a database cluster available during backups?

The backup window, the scheduled time for the database cluster’s full daily backup, is from 01:00 to 05:00 (UTC+3).

Clusters remain fully available during the backup window.

Can I change the retention period for automatic backups?Can I change the retention period for automatic backups?

You can set the retention period for automatic backups when creating or updating a cluster.

What metrics and processes can be monitored?What metrics and processes can be monitored?

For all DBMS types, you can monitor:

• CPU, memory, network, and disk usage, in absolute terms.
• Memory, network, and disk usage as a percentage of the set limits for the relevant cluster's host class.
• Amount of data in a DB cluster and the remaining free space in your data storage.

For DB hosts, you can monitor metrics specific to their DBMS type. For example, for Yandex StoreDoc, you can track:

• Number of queries per second.
• Disk space used.
• Number of connections, etc.

Monitoring can be performed with a minimum granularity of five seconds.

How do I set up an alert that triggers as soon as a certain percentage of disk space is used up?How do I set up an alert that triggers as soon as a certain percentage of disk space is used up?

Create an alert for the disk.used_bytes metric in Yandex Monitoring. This metric shows the disk space usage in the Yandex StoreDoc cluster.

For disk.used_bytes, use notification thresholds. Their recommended values are as follows:

• Alarm: 90% of disk space
• Warning: 70% of disk space

Thresholds are set in bytes only. For example, the recommended values for a 100 GB disk are as follows:

• Alarm: 96636764160 bytes (90%)
• Warning: 75161927680 bytes (70%)

Questions about Yandex StoreDocQuestions about Yandex StoreDoc

Why should I use Yandex StoreDoc in Yandex StoreDoc rather than my own VM-based installation?Why should I use Yandex StoreDoc in Yandex StoreDoc rather than my own VM-based installation?

Yandex StoreDoc automates routine database maintenance:

• Quick DB deployment with the required available resources.
• Data backup.
• Regular software updates.
• Ensuring DB cluster fault tolerance.
• Database usage monitoring and statistics.

What happens to a cluster if one of its hosts fails?What happens to a cluster if one of its hosts fails?

If there are more than one replica in the database cluster, it will continue working if a host fails.

The only way data may be lost is if the cluster's only host fails.

Can I deploy a Yandex StoreDoc cluster in multiple availability zones?Can I deploy a Yandex StoreDoc cluster in multiple availability zones?

Yes. A database cluster may consist of hosts that reside in different availability zones and even different availability regions.

What is the backup procedure for Yandex StoreDoc clusters?What is the backup procedure for Yandex StoreDoc clusters?

Backups are created every 24 hours and retained for seven days. You can only restore data as of the backup creation time.

How does replication work for Yandex StoreDoc?How does replication work for Yandex StoreDoc?

Yandex StoreDoc uses the standard Yandex StoreDoc replication mechanism: if a cluster has more than one active host, one of them is automatically selected as the primary server to handle write requests.

What limitations are there for Yandex StoreDoc database clusters?What limitations are there for Yandex StoreDoc database clusters?

For more info on limitations in Yandex StoreDoc, see the Quotas and limits section.

Why is my cluster slow even though there are still some computing resources to spare?Why is my cluster slow even though there are still some computing resources to spare?

Your storage may have insufficient maximum IOPS and bandwidth to process the current number of requests. In this case, throttling occurs, which degrades the entire cluster performance.

The maximum IOPS and bandwidth values increase by a fixed value when the storage size increases by a certain step. The step and increment values depend on the disk type:

To increase the maximum IOPS and bandwidth values and make throttling less likely, increase the storage size when updating your cluster.

If you are using the network-hdd storage type, consider switching to network-ssd or network-ssd-nonreplicated by restoring the cluster from a backup.

How do I get access to the local.oplog.rs service collection?How do I get access to the local.oplog.rs service collection?

To grant a user read access to oplog, assign them the mdbReplication role in the admin database. Do it by executing the following command in the Yandex Cloud CLI:

yc managed-mongodb user update <username> \
  --cluster-name <cluster_name> \
  --permission database=admin,role=mdbReplication,role=<other_role>,... \
  --permission database=<other_DB_name>,role=<role>,...

To avoid deleting user roles that are already assigned, list both the existing and new roles in the command.

Can I connect to cluster hosts over SSH or get superuser privileges on hosts?Can I connect to cluster hosts over SSH or get superuser privileges on hosts?

You cannot connect to hosts via SSH. This is done for the sake of security and user cluster fault tolerance because direct changes inside a host can render it completely inoperable.

What should I do if I get a revocation check error when using PowerShell to obtain an SSL certificate?What should I do if I get a revocation check error when using PowerShell to obtain an SSL certificate?

Here is the full text of the error:

curl: (35) schannel: next InitializeSecurityContext failed: Unknown error (0x80092012)
The revocation function was unable to check revocation for the certificate

This means, when connecting to the website, the service was unable to check whether or not its certificate was listed among revoked ones.

To fix this error:

• Make sure the corporate network settings do not block the check.

• Run the following command with the --ssl-no-revoke parameter:

   mkdir $HOME\.mongodb; curl.exe --ssl-no-revoke -o $HOME\.mongodb\root.crt https://storage.yandexcloud.net/cloud-certs/CA.pem