Operating System Requirements

PostgreSQL can be deployed on a number of platforms. A platform consists of a CPU architecture and operating system. The current supported platforms can be found in the PostgreSQL documentation.

The relevant operating system and associated recommendations can be found below :

Operating System	Recommendations
Red Hat Enterprise Linux/ CentOS / Oracle Linux/Ubuntu/SUSE/Debian	The recommended settings for Linux operating systems can be found in the Linux Recommended Settings. In addition to the existing best practices ensure that the number of requests per volume is set to a higher value. Increasing this value allows individual volumes to service more storage requests at any single time. Add the following to the udev rules file for FlashArray to increase the maximum number of requests for a single volume: `Set DM devices number of requests to 1024 or higher. This uses 1MB of memory per request ACTION=="add\|change", KERNEL=="dm-[0-9]", SUBSYSTEM=="block", ENV{DM_NAME}=="3624a937", ATTR{queue/nr_requests}="1024"`
Microsoft Windows Server	The best practices for Microsoft Windows can be set using the Validate Windows Server with Test-Pfa2WindowsBestPractices Cmdlet.

Operating System

Recommendations

Red Hat Enterprise Linux/ CentOS / Oracle Linux/Ubuntu/SUSE/Debian

The recommended settings for Linux operating systems can be found in the Linux Recommended Settings.

In addition to the existing best practices ensure that the number of requests per volume is set to a higher value. Increasing this value allows individual volumes to service more storage requests at any single time.

Add the following to the udev rules file for FlashArray to increase the maximum number of requests for a single volume:


Set DM devices number of requests to 1024 or higher. This uses 1MB of memory per request
ACTION=="add|change", KERNEL=="dm-[0-9]*", SUBSYSTEM=="block", ENV{DM_NAME}=="3624a937*", ATTR{queue/nr_requests}="1024"

Microsoft Windows Server

The best practices for Microsoft Windows can be set using the Validate Windows Server with Test-Pfa2WindowsBestPractices Cmdlet.

File System Configuration

The recommended file systems for PostgreSQL with FlashArray are NTFS (Microsoft Windows) , XFS (Linux) and EXT4 (Linux).

Microsoft Windows

The default allocation unit size (4K) for NTFS filesystems works well with PostgreSQL.

Linux

XFS

When using the XFS file system the default options are typically all that is required.

XFS file systems can be created on a FlashArray volume using the command:


mkfs.xfs /dev/mapper/<device>

The default options in /etc/fstab should be used with XFS in the majority of cases. Using noatime can yield additional performance benifits in some scenarios.


/dev/mapper/<device> /mountpoint xfs defaults 0 0

If using iSCSI connectivity to FlashArray ensure the _netdev,nofail options are present:


/dev/mapper/<device> /mountpoint xfs _netdev,nofail 0 0

For systems using the Linux Kernel 4.13 or later the "nobarrier" option is deprecated for XFS. To increase the possible performance of the volume add the following udev rule to the existing rules file:

FCP and iSCSI


ACTION=="add|change", KERNEL=="sd*[!0-9]", SUBSYSTEM=="block", ENV{ID_VENDOR}=="PURE", ATTR{queue/write_cache}="write through"
ACTION=="add|change", KERNEL=="dm-[0-9]*", SUBSYSTEM=="block", ENV{DM_NAME}=="3624a937*", ATTR{queue/write_cache}="write through"

NVMe-oF connectivity


ACTION=="add|change", KERNEL=="nvme*[!0-9]", SUBSYSTEM=="block", ATTR{queue/write_cache}="write through"
ACTION=="add|change", KERNEL=="dm-[0-9]*", SUBSYSTEM=="block", ENV{DM_NAME}=="eui.00723ec7b5b427*", ATTR{queue/write_cache}= "write through"

Once the rules have been added reload and apply them using the udevadm utility:


 udevadm control --reload-rules && udevadm trigger

EXT4

The EXT4 file system should be created with the "-o discard" option to enable automating unmap.


mkfs.ext4 -o discard /dev/mapper/<device>

With EXT4 the volume can be mounted using /etc/fstab with the default options but to increase the possible performance the "noatime" and "barrier=0" options should be used.


/dev/mapper/<device> /mountpoint ext4 noatime,barrier=0 0 0

If using iSCSI connectivity to FlashArray ensure the _netdev,nofail options are present:


/dev/mapper/<device> /mountpoint ext4 _netdev,nofail,noatime,barrier=0 0 0

Adding an entry to /etc/fstab

Entries in /etc/fstab can be done using the device path or the UUID of the filesystem.

To get the UUID of a file system use the blkid command and match the device to the respective UUID.


[root@DB-01 ~]# blkid
/dev/sdb: PTUUID="91360acd-7332-47d9-9027-0300c7e3a081" PTTYPE="gpt"
/dev/sda: PTUUID="91360acd-7332-47d9-9027-0300c7e3a081" PTTYPE="gpt"
/dev/sdc: PTUUID="91360acd-7332-47d9-9027-0300c7e3a081" PTTYPE="gpt"
/dev/mapper/3624a93708488b6dac70f42a20001ec55: PTUUID="91360acd-7332-47d9-9027-0300c7e3a081" PTTYPE="gpt"
/dev/sdd: PTUUID="91360acd-7332-47d9-9027-0300c7e3a081" PTTYPE="gpt"
/dev/mapper/3624a93708488b6dac70f42a20001ec55p1: UUID="D759-B5A6" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="8f317ff7-97f5-48ab-83d8-f54d647fb390"
/dev/mapper/3624a93708488b6dac70f42a20001ec55p2: UUID="97d13054-20c7-436e-b6ab-ef8b8f3ce46b" BLOCK_SIZE="512" TYPE="xfs" PARTUUID="2644a548-dde5-4ac8-8679-c100011a0d78"
/dev/mapper/3624a93708488b6dac70f42a20001ec55p3: UUID="GXujto-h3yl-V3hq-jFZs-3xd6-RhLB-0vFf8l" TYPE="LVM2_member" PARTUUID="380fbf39-eb6e-4bf0-ae25-f4abd6f02803"
/dev/mapper/rhel-root: UUID="5547b1a3-590a-4d54-9d0b-710714ca7e52" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/rhel-swap: UUID="70470107-9368-4d32-82d8-7620f1cdc665" TYPE="swap"
/dev/mapper/rhel-home: UUID="0e08dae8-3d93-451c-a021-b3fe58f9b464" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme0n1: UUID="36202f29-95e8-49d2-a200-4057712b9236" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme0n2: UUID="489e7195-46b5-466a-8770-9aa7938c8afb" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme0n3: UUID="0f4da946-a86e-4fd3-bcd3-0d74d88ef83b" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme0n4: UUID="9a5e14cc-b226-4f7c-91a5-f8397a73b5bd" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme0n5: UUID="41e4a009-b98a-4d48-9d69-f45e717485e2" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/eui.00668f1ab9b15f4b24a937c400011884: UUID="36202f29-95e8-49d2-a200-4057712b9236" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme1n1: UUID="36202f29-95e8-49d2-a200-4057712b9236" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme1n2: UUID="489e7195-46b5-466a-8770-9aa7938c8afb" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme1n3: UUID="0f4da946-a86e-4fd3-bcd3-0d74d88ef83b" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme1n4: UUID="9a5e14cc-b226-4f7c-91a5-f8397a73b5bd" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme1n5: UUID="41e4a009-b98a-4d48-9d69-f45e717485e2" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme2n1: UUID="36202f29-95e8-49d2-a200-4057712b9236" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme2n2: UUID="489e7195-46b5-466a-8770-9aa7938c8afb" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme2n3: UUID="0f4da946-a86e-4fd3-bcd3-0d74d88ef83b" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme2n4: UUID="9a5e14cc-b226-4f7c-91a5-f8397a73b5bd" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme2n5: UUID="41e4a009-b98a-4d48-9d69-f45e717485e2" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme3n1: UUID="36202f29-95e8-49d2-a200-4057712b9236" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme3n2: UUID="489e7195-46b5-466a-8770-9aa7938c8afb" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme3n3: UUID="0f4da946-a86e-4fd3-bcd3-0d74d88ef83b" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme3n4: UUID="9a5e14cc-b226-4f7c-91a5-f8397a73b5bd" BLOCK_SIZE="512" TYPE="xfs"
/dev/nvme3n5: UUID="41e4a009-b98a-4d48-9d69-f45e717485e2" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/eui.00668f1ab9b15f4b24a937c400011890: UUID="489e7195-46b5-466a-8770-9aa7938c8afb" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/eui.00668f1ab9b15f4b24a937c400011898: UUID="0f4da946-a86e-4fd3-bcd3-0d74d88ef83b" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/eui.00668f1ab9b15f4b24a937c4000118a0: UUID="9a5e14cc-b226-4f7c-91a5-f8397a73b5bd" BLOCK_SIZE="512" TYPE="xfs"
/dev/mapper/eui.00668f1ab9b15f4b24a937c4000118a1: UUID="41e4a009-b98a-4d48-9d69-f45e717485e2" BLOCK_SIZE="512" TYPE="xfs"

Then use the UUID in place of the device path (works for both ext4 and XFS):


UUID=489e7195-46b5-466a-8770-9aa7938c8afb /mountpoint ext4 _netdev,nofail,noatime,barrier=0 0 0