Scratch Disk (EXT4)

When using FMADIO Packet capture system for analytics processing SSD resources can be split into Capture devices and Scratch disk space. In scratch disk space 1-16TB of SSD can be mounted as a general purpose file system used to store temporarily/intermediate network packet processing results.

The system should have scratch disks setup and visible on the GUI as follows, if this has not been configured contact [e-mail] on how to configure

FMADIO Scratch Disk Network Analytics processing space

In the above example there are 2 disks SCR0 and SCR1 enabled for scratch disk these are seen on the file system as

fmadio@fmadio20v3-287:~$ ls -al /opt/fmadio/disk/scr*
lrwxrwxrwx    1 root     root            12 Jun  6 17:02 /opt/fmadio/disk/scr0 -> /dev/nvme2n1
lrwxrwxrwx    1 root     root            12 Jun  6 17:02 /opt/fmadio/disk/scr1 -> /dev/nvme0n1
fmadio@fmadio20v3-287:~$

NOTE: the /dev/* mount point may change from time to time, please use the /opt/fmadio/disk/scr* path name for all operations.

NOTE: Any change to the scratch disk configuration it is recommend to run a Quick Format to ensure SSD and Capture disks configuration are consistent

Specifcying Sratch Disks

By default all SSD are specified are dedicated to capture. This is specified in the configuration file

/opt/fmadio/etc/disk.lua

Capture disks are specified here

CacheDisk =
{
    ["S462NF0MA04379A"] = "ssd0",
    ["S462NF0MA05134B"] = "ssd1",
    ["S5JXNG0N108745Y"] = "ssd2",
    ["S5JXNG0N108746D"] = "ssd3",
}

In the above example we have 4 x SSD for capture. To convert half to capture and half to scratch disk modify as follows

CacheDisk =
{
    ["S462NF0MA04379A"] = "ssd0",
    ["S462NF0MA05134B"] = "ssd1",
}
,
ScratchDisk =
{
    ["S5JXNG0N108745Y"] = "scr0",
    ["S5JXNG0N108746D"] = "scr1",
}

This is assigning the SSD Serial numbers to mount point /opt/fmadio/disk/scr0 and /opt/fmadio/disk/scr1. The actual Serial numbers for each system will be different, the mount point (scr0/scr1) is the same.

After updating confirm there are no syntax errors in the config file by running fmadiolua /opt/fmadio/etc/disk.lua as follows

fmadio@fmadio20n40v3-363:~$ fmadiolua /opt/fmadio/etc/disk.lua
fmad fmadlua Jun 13 2021
calibrating...
0 : 2992970378           2.9930 cycles/nsec offset:7.030 Mhz
Cycles/Sec 2992970378.0000 Std:       0 cycle std(  0.00000000) Target:3.00 Ghz
argv fmadiolua
failed to open self? [fmadiolua]
loading filename [/opt/fmadio/etc/disk.lua]
done 0.000038Sec 0.000001Min
fmadio@fmadio20n40v3-363:~$

Output as above shows correctly formatted file. Output per below shows configuration file with a syntax error (line 30 has some incorrect formatting)

fmadio@fmadio20n40v3-363:~$ fmadiolua /opt/fmadio/etc/disk.lua
fmad fmadlua Jun 13 2021
calibrating...
0 : 2992970368           2.9930 cycles/nsec offset:7.030 Mhz
Cycles/Sec 2992970368.0000 Std:       0 cycle std(  0.00000000) Target:3.00 Ghz
argv fmadiolua
failed to open self? [fmadiolua]
loading filename [/opt/fmadio/etc/disk.lua]
load status: 3 0
/opt/fmadio/etc/disk.lua:30: '}' expected (to close '{' at line 2) near 'ScratchDisk'
fmadio@fmadio20n40v3-363:~$

After confirming the configuration file syntax is correct, reboot the system. The mount points scr0 and scr1 should be visible as shown below.

fmadio@fmadio20n40v3-363:~$ ls -al /opt/fmadio/disk/scr*
lrwxrwxrwx    1 root     root            12 Jun  6 17:02 /opt/fmadio/disk/scr0 -> /dev/nvme2n1
lrwxrwxrwx    1 root     root            12 Jun  6 17:02 /opt/fmadio/disk/scr1 -> /dev/nvme0n1
fmadio@fmadio20n40v3-363:~$

Creating RAID0 partition

After /opt/fmadio/disk/scr[0-1] have been created. Next is creating a /dev/md1 RAID0 partition as follows

fmadio@fmadio20v3-287:~$ sudo mdadm --create /dev/md1 --force --level=raid0 --raid-devices=2 /opt/fmadio/disk/scr0 /opt/fmadio/disk/scr1
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md1 started.
fmadio@fmadio20v3-287:~$

This creates a /dev/md1 partition as shown with lsblk command. Can see the /dev/md1 device

fmadio@fmadio20v3-287:~$ lsblk
NAME    MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
sdd       8:48   0   3.7T  0 disk
sdb       8:16   0   3.7T  0 disk
nvme2n1 259:0    0 447.1G  0 disk
`-md1     9:1    0   894G  0 raid0
nvme1n1 259:3    0   477G  0 disk
sde       8:64   0   3.7T  0 disk
sdc       8:32   0   3.7T  0 disk
sda       8:0    0 238.5G  0 disk
|-sda2    8:2    0 223.6G  0 part  /mnt/store0
`-sda1    8:1    0  14.9G  0 part  /mnt/sda1
nvme0n1 259:1    0 447.1G  0 disk
`-md1     9:1    0   894G  0 raid0
nvme3n1 259:2    0   477G  0 disk
fmadio@fmadio20v3-287:~$

More detail via the mdadm --detail command

fmadio@fmadio20v3-287:~$ sudo mdadm --detail /dev/md1
/dev/md1:
        Version : 1.2
  Creation Time : Sun Jun  6 17:43:12 2021
     Raid Level : raid0
     Array Size : 937440256 (894.01 GiB 959.94 GB)
   Raid Devices : 2
  Total Devices : 2
    Persistence : Superblock is persistent

    Update Time : Sun Jun  6 17:43:12 2021
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

     Chunk Size : 512K

           Name : fmadio20v3-287:1  (local to host fmadio20v3-287)
           UUID : 06234ac8:694ae295:3659e4fc:b59a7d55
         Events : 0

    Number   Major   Minor   RaidDevice State
       0     259        0        0      active sync   /dev/nvme2n1
       1     259        1        1      active sync   /dev/nvme0n1
fmadio@fmadio20v3-287:~$

Create EXT4 Filesystem

The block device /dev/md1 is block level only, it contains no mountable file system. Next create btrfs filesystem on the device as follows

fmadio@fmadio20v3-287:~$ sudo mkfs.ext4 /dev/md1

< update me >

fmadio@fmadio20v3-287:~$

Mount the Scratch Filesystem

By default FMADIO Packet Capture systems at boot time will start the RAID0 partition and mount /dev/md1 Scratch disk to /mnt/store1

If it fails to mount, please issue the following command

fmadio@fmadio20v3-287:~$ sudo mount -t ext4 /dev/md1 /mnt/store1
fmadio@fmadio20v3-287:~$