SQL Server on Linux: Known issues

The following sections describe known issues with SQL Server on Linux.

General

The following table lists the most common issues with SQL Server on Linux.

Issue	Resolution
The length of the hostname where SQL Server is installed needs to be 15 characters or less.	Change the name in /etc/hostname to a value 15 characters long or less.
Manually setting the system time backward in time causes SQL Server to stop updating the internal system time within the Database Engine.	Restart SQL Server.
Only single instance installations are supported.	If you want to have more than one instance on a given host, consider using virtual machines or Linux containers.
SQL Server Configuration Manager can't connect to SQL Server on Linux.	None.
The default language of the sa login is English.	Change the language of the sa login with the ALTER LOGIN statement.
The OLE DB provider logs the following warning: Failed to verify the Authenticode signature of 'C:\binn\msoledbsql.dll'. Signature verification of SQL Server DLLs will be skipped. Genuine copies of SQL Server are signed. Failure to verify the Authenticode signature might indicate that this isn't an authentic release of SQL Server. Install a genuine copy of SQL Server or contact customer support.	No action is required. The OLE DB provider is signed using SHA256. The SQL Server Database Engine doesn't validate the signed .dll correctly.
The Reset password command using mssql-conf throws the following error: Unable to set the system administrator password. Please consult the ERRORLOG in /path for more information.	The error message is a false negative. The password reset was successful, and you can continue using the new password. Applies to: SQL Server 2022 (16.x) container images only.

Databases

• The master database can't be moved with the mssql-conf utility. Other system databases can be moved with mssql-conf.

• When you restore a database that was backed up on SQL Server on Windows, you must use the WITH MOVE clause in the Transact-SQL statement. For more information, see Migrate a SQL Server database from Windows to Linux using backup and restore.

• Certain algorithms (cipher suites) for Transport Layer Security (TLS) don't work properly with SQL Server on Linux. This results in connection failures when attempting to connect to SQL Server, and problems establishing connections between replicas in high availability groups.

  To resolve this issue, modify the mssql.conf configuration script for SQL Server on Linux to disable problematic cipher suites, by following these steps:

  1. Add the following section to /var/opt/mssql/mssql.conf. The exclamation symbol (!) negates the expression. This tells OpenSSL not to use the cipher suite that follows.

     [network]
     tlsciphers=AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:!ECDHE-RSA-AES128-GCM-SHA256:!ECDHE-RSA-AES256-GCM-SHA384:!ECDHE-ECDSA-AES256-GCM-SHA384:!ECDHE-ECDSA-AES128-GCM-SHA256:!ECDHE-ECDSA-AES256-SHA384:!ECDHE-ECDSA-AES128-SHA256:!ECDHE-ECDSA-AES256-SHA:!ECDHE-ECDSA-AES128-SHA:!ECDHE-RSA-AES256-SHA384:!ECDHE-RSA-AES128-SHA256:!ECDHE-RSA-AES256-SHA:!ECDHE-RSA-AES128-SHA:!DHE-RSA-AES256-GCM-SHA384:!DHE-RSA-AES128-GCM-SHA256:!DHE-RSA-AES256-SHA:!DHE-RSA-AES128-SHA:!DHE-DSS-AES256-SHA256:!DHE-DSS-AES128-SHA256:!DHE-DSS-AES256-SHA:!DHE-DSS-AES128-SHA:!DHE-DSS-DES-CBC3-SHA:!NULL-SHA256:!NULL-SHA
     

  2. Restart SQL Server with the following command.

     sudo systemctl restart mssql-server
     

• SQL Server 2014 (12.x) databases on Windows that use In-Memory OLTP can't be restored to SQL Server on Linux. If your SQL Server 2014 (12.x) database uses In-Memory OLTP, first upgrade the databases to a newer version of SQL Server on Windows. Then you can move it to SQL Server on Linux, with backup/restore, or detach/attach.

• User permission ADMINISTER BULK OPERATIONS isn't supported on Linux at this time.

• TDE-compressed backups that are made using SQL Server 2019 (15.x) CU 16 and later versions can't be restored to previous CU versions of SQL Server 2019 (15.x). For more information, see FIX: Error 3241 occurs during executing RESTORE LOG or RESTORE DATABASE.

  Transparent Data Encryption (TDE)-compressed backups that are made using previous CU versions of SQL Server 2019 (15.x) can still be restored by using SQL Server 2019 (15.x) CU 16 and later versions.

• When you install SQL Server 2022 (16.x) on Ubuntu 22.04, you might see the following error message: Failed to start Microsoft SQL Server Database Engine. If you review the error log, you see an incorrect path for the system databases.

  To work around this issue, start the instance in single-user mode, and use ALTER DATABASE ... MODIFY FILE to move the configured location of the system databases to the default location /var/opt/mssql/data. After making this change, restart the service.

Network

Features that involve outbound TCP connections from the sqlservr process, such as linked servers, PolyBase, or availability groups, might not work if both the following conditions are met:

• The target server is specified as a hostname and not an IP address.

• The source instance has IPv6 disabled in the kernel. To verify if your system has IPv6 enabled in the kernel, all the following tests must pass:

  • cat /proc/cmdline prints the boot cmdline of the current kernel. The output must not contain ipv6.disable=1.
  • The /proc/sys/net/ipv6/ directory must exist.
  • A C program that calls socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) should succeed - the syscall must return an fd != -1 and not fail with EAFNOSUPPORT.

The exact error depends on the feature. For linked servers, you see a login timeout error. For availability groups, the ALTER AVAILABILITY GROUP JOIN DDL on the secondary will fail after five minutes with a download configuration timeout error.

To work around this issue, do one of the following options:

• Use IPs instead of host names to specify the target of the TCP connection.

• Enable IPv6 in the kernel by removing ipv6.disable=1 from the boot command line. The method depends on the Linux distribution and the bootloader, such as grub. If you want IPv6 to be disabled, you can still disable it by setting net.ipv6.conf.all.disable_ipv6 = 1 in the sysctl configuration (for example, /etc/sysctl.conf). Although this setting prevents the system's network adapter from getting an IPv6 address, it allows the sqlservr features to work.

TLS 1.3 not supported

Applies to: SQL Server 2022 (16.x) only.

Although TLS 1.3 is supported on SQL Server 2022 (16.x) for Windows, you must use TLS 1.2 on Linux.

Network File System (NFS)

If you use Network File System (NFS) remote shares in production, note the following support requirements:

• Use NFS version 4.2 or later versions. Older versions of NFS don't support required features, such as fallocate and sparse file creation, common to modern file systems.

• Locate only the /var/opt/mssql directories on the NFS mount. Other files, such as the SQL Server system binaries, aren't supported.

• Ensure that NFS clients use the nolock option when mounting the remote share.

Localization

• If your locale isn't English (en_us) during setup, you must use UTF-8 encoding in your bash session/terminal. If you use ASCII encoding, you might see an error similar to the following output:

  UnicodeEncodeError: 'ascii' codec can't encode character u'\xf1' in position 8: ordinal not in range(128)

  If you can't use UTF-8 encoding, run setup using the MSSQL_LCID environment variable to specify your language choice.

  sudo MSSQL_LCID=<LcidValue> /opt/mssql/bin/mssql-conf setup
  

• When you run mssql-conf setup, and perform a non-English installation of SQL Server, incorrect extended characters can be displayed after the localized text, "Configuring SQL Server...". Or, for non-Latin based installations, the sentence might be missing completely. The missing sentence should display the following localized string:

  The licensing PID was successfully processed. The new edition is [<Name> edition].

  This string is output for information purposes only, doesn't affect the successful installation of SQL Server in any way.

Full-Text Search

Not all filters are available with this release, including filters for Microsoft Office documents. For a list of supported filters, see Install SQL Server Full-Text Search on Linux.

SQL Server Integration Services (SSIS)

The mssql-server-is package isn't supported on SUSE Linux Enterprise Server (SLES). The package is supported on Ubuntu, and Red Hat Enterprise Linux (RHEL).

Integration Services packages can use ODBC connections on Linux. This functionality was tested with the SQL Server and the MySQL ODBC drivers, but is also expected to work with any Unicode ODBC driver that observes the ODBC specification. At design time, you can provide either a DSN or a connection string to connect to the ODBC data; you can also use Windows authentication. For more info, see the blog post announcing ODBC support on Linux.

The following features aren't supported in this release when you run SSIS packages on Linux:

• Integration Services Catalog database
• Scheduled package execution by SQL Server Agent
• Windows Authentication
• Third-party components
• Change data capture (CDC)
• Integration Services Scale Out
• Azure Feature Pack for SSIS
• Hadoop and HDFS support
• Microsoft Connector for SAP BW

For a list of built-in SSIS components that aren't currently supported, or that are supported with limitations, see Limitations and known issues for SSIS on Linux.

For more info about SSIS on Linux, see the following articles:

• Blog post announcing SSIS support for Linux.
• Install SQL Server Integration Services (SSIS) on Linux
• Extract, transform, and load data on Linux with SSIS

SQL Server Management Studio (SSMS)

The following limitations apply to SQL Server Management Studio on Windows connected to SQL Server on Linux.

• Maintenance plans aren't supported.

• Management Data Warehouse (MDW) and the data collector in SQL Server Management Studio aren't supported.

• SQL Server Management Studio UI components that have Windows Authentication or Windows event log options don't work with Linux. You can still use these features with other options, such as SQL Server logins.

• The number of log files to retain can't be modified.

High availability and disaster recovery

Applies to: SQL Server 2022 (16.x) only.

When you run SQL Server 2022 (16.x) on RHEL 9 as a confined application with SELinux enabled, Pacemaker clustering might not work as expected. You must install SQL Server 2022 (16.x) as an unconfined application with SELinux turned on, to make use of Pacemaker clustering capabilities.

Machine Learning Services

Applies to: SQL Server 2022 (16.x) only.

For SQL Server 2022 (16.x) packages for RHEL 9 and Ubuntu 22.04, there are some prerequisites to take into account with cgroup-v1, before installing Machine Learning Services.

RHEL 9

1. As a prerequisite, cgroup-v1 needs to be enabled as per Using cgroupfs to manually manage cgroups Red Hat Enterprise Linux 9 from Red Hat.

2. Then follow instructions to install SQL Machine Learning Services as documented.

3. Disable network namespace isolation.

   sudo /opt/mssql/bin/mssql-conf set extensibility outboundnetworkaccess 1
   

4. Restart mssql-launchpadd service for these changes to take effect.

   sudo systemctl restart mssql-launchpadd
   

Ubuntu 22.04

For Ubuntu 22.04, you should reach out to Canonical directly for the exact steps. Based on the available information, here's a summary of the steps that are needed. We don't recommend these steps on a production workload.

1. Open the grub bootloader configuration file located at /etc/default/grub.

   sudo vi /etc/default/grub
   

2. Find the line starting with GRUB_CMDLINE_LINUX_DEFAULT= and append systemd.unified_cgroup_hierarchy=0 to the string value of this parameter. The result should be something like the following output:

   GRUB_CMDLINE_LINUX_DEFAULT="quiet splash systemd.unified_cgroup_hierarchy=0"
   

   Save the file and exit the editor.

3. Update grub and reboot the system.

   sudo update-grub
   sudo reboot
   

4. Once the system finishes the reboot, verify that cgroup-v1 is set up correctly, by checking the cgroup mount points.

   mount | grep cgroup
   

   The output should look as follows, you should see cgroup without a number suffix in the output:

   tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,size=4096k,nr_inodes=1024,mode=755,inode64)
   cgroup2 on /sys/fs/cgroup/unified type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate)
   cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,name=systemd)
   cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
   cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
   cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
   cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)
   cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
   cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
   cgroup on /sys/fs/cgroup/rdma type cgroup (rw,nosuid,nodev,noexec,relatime,rdma)
   cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
   cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
   cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
   cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
   cgroup on /sys/fs/cgroup/misc type cgroup (rw,nosuid,nodev,noexec,relatime,misc)
   

   Once you have enabled cgroup-v1 for Ubuntu 22.04, follow the steps in Install SQL Server 2022 Machine Learning Services (Python and R) on Linux, to install and enable SQL Machine Learning Service for SQL Server 2022 (16.x) packages on Ubuntu 22.04.

Related content

• Release notes for SQL Server 2022 on Linux
• Editions and supported features of SQL Server 2022 (16.x) on Linux
• Troubleshoot SQL Server on Linux