Compression Function Testing

For compression function testing:

Compression is available per volume.
Lightbits can support a compression ratio of up to 4:1. Our TCO models target a 2:1 compression ratio.
Lightbits uses LZ4 and we compress every 4KB block independently. LZ4 is a well known algorithm, which has a good balance between compression ratio and performance (compression speed/decompression speed).

Test Case

Create two new volumes: one with compression=true and one with compression=false.
Use FIO to perform random write operations on the two new volumes on the client server.
From the Lightbits cluster, check the ratio of capacity and physical use of the newly created volume, and calculate the compression ratio.
Record the performance data of the client server performing IO on two different disks, and compare the performance differences.

To do this, first run a quick cleanup process to delete previously used volumes (to start fresh):

From the client server, disconnect previously used NVMe devices. Note that this is not mandatory; it’s only to see a clean and fresh process.

Bash
    
 
nvme disconnect-all
Copy

After the NVMe disconnection, no old NVMe devices will be attached.

Bash
    
 
root@rack07-server56:~ nvme disconnect -allroot@rack07-server56:~ lsblkNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTsda 8:0 0 223.6G 0 disk|-sda2 8:2 0 1G 0 part /boot|-sda3 8:3 0 222.6G 0 part| |-inaugurator--v2-osmosis--cache 253:1 0 30G 0 lvm| |-inaugurator--v2-root 253:2 0 147.7G 0 lvm /| -inaugurator--v2-swap 253:0 0 8G 0 lvm [SWAP]sda1 8:1 0 2M 0 part
Copy

Delete volumes from the Lightbits cluster, until you have no volumes:

Bash
    
 
root@rack03-server72:~ lbcli list volumesName UUID State Protection StateNSID Size Replicas Compression ACL Rebuild Progressvol1 01b20f49-13d6-468f-b82d-752594922a6e Available FullyProtected 2 25 GiB 1 false values:"acl3" Noneclone_snap1 30242a3b-cf7d-4a1e-ae0c-14295b631ebf Available FullyProtected 3 25 GiB 1 false values:"acl3" Nonevol65 b1c49657-d4a5-4cf8-b8fd-13a0bd0e1358 Available FullyProtected 5 55 GiB 1 false values:"acl3" Nonevol_comp1 b95efd8f-f93d-40de-b2d3-32d3780376a5 Available FullyProtected 7 30 GiB 1 false values:"acl3" None1vol c074cf03-83fb-4c15-a601-5444e798f51f Available FullyProtected 4 200 GiB 2 true values:"acl3" Nonevol_not_comp1 f0c8693d-4be1-4a44-8078-b4fcd777bae4 Deleting FullyProtected 6 30 GiB 1 true values:"acl3" None
Copy

Example

lbcli delete volume --name=1vol --project-name=default

Repeat this command until you have no volumes retrieved on the Lightbits cluster.

Create two new volumes: 1 with compression=true and 1 with compression=false.

No compression:

Bash
    
lbcli create volume --size="30 Gib" --name=vol1_not_compressed --acl="acl3" --compression=false --replica-count=1 --project-name=default
Copy

With compression:

Bash
    
lbcli create volume --size="50 Gib" --name=vol1_compressed --acl="acl3" --compression=true --replica-count=1 --project-name=default
Copy

Check that the volumes are created:

Bash
    
 
lbcli list volumes
Copy

Sample Output

Bash
    
 
root@rack03-server72:~ lbcli list volumesName UUID State ProtectionState NSID Size Replicas Compression ACL RebuildProgressvol1_not_compressed 109a6228-6885-45d2-8ba2-f03541aafa4d Available FullyProtected 9 30 GiB 1 false values:"acl3" Nonevol1_compressed 853044a6-6ff9-49a0-bffa-0939aee7f4fd Available FullyProtected 11 50 GiB 1 true values:"acl3" None
Copy

From the client server, connect to the newly-created volumes and check that the new 30 Gib NVMe (compressed) and 50 Gib NVMe (not compressed) are attached, with lsblk:

Get and copy cluster NQN:

Bash
    
 
lbcli get cluster
Copy

Sample Output

Bash
    
root@rack11-server93:~ lbcli get clusterUUID Subsystem NQN Current max replicas Supported max replicas MinVersionInCluster MinAllowedVersion MaxAllowedVersion2ac0b5f1-e332-4526-9799-e5cec2208837 nqn.2016-01.com.lightbitslabs:uuid:1fa41a41-cf47-4ebd-b0f4-babda5fe322c 3 3 2.3.12~b793 2.3.X
Copy

Connect to the volume to attach the NVMe device to the client (this can be executed with a simple ‘for’ loop as well.)

Bash
    
LIGHTBITS_CONTROLLER_IPS="172.16.231.70 172.16.231.71 172.16.231.72"; for CONTROLLER_IP in $LIGHTBITS_CONTROLLER_IPS; do nvme connect -t tcp -a $CONTROLLER_IP --ctrl-loss-tmo -1 -n $LIGHTBITS_CLUSTER_NQN -s 4420 -q $VOLUME_ACL; done
Copy

Check that the volumes are mapped:

Bash
    
 
lsblk
Copy

Sample Output

Bash
    
 
root@rack07-server56 :~ lsblkNAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTnvme0n1 259:1 0 50G 0 disknvme0n2 259:3 0 30G 0 disksda 8:0 0 111.8G 0 disk|-sda2 8:2 0 1G 0 part /boot|-sda3 8:3 0 110.8G 0 part| |-inaugurator--v2-osmosis--cache 253:1 0 30G 0 lvm| |-inaugurator--v2-root 253:2 0 58.2G 0 lvm /| `-inaugurator--v2-swap 253:0 0 8G 0 lvm [SWAP]`-sda1
Copy

Use FIO to perform random write operations on the two new volumes on the client server.

Create a file named job-file:

Bash
    
 
touch job-file.fio
Copy

Paste the contents of the following code snippet into the file:

Bash
    
 
[global]ramp_time=0rw=randwrite # WRITE#rwmixread=100 # When using randrw in the line aboverefill_buffersloops=1buffer_compress_percentage=70buffer_compress_chunk=4096direct=1norandommap=1time_basedlog_avg_msec=1000numjobs=12 # Max value is number of CPU coresiodepth=32randrepeat=0ioengine=libaiogroup_reporting=1runtime=300bs=4k[job_compressed]filename=/dev/nvme0n1 # Device path of compressed volume[job_not_compressed]filename=/dev/nvme0n2 # Device path of non-compressed volume
Copy

Run FIO Jobs:

Bash
    
 
fio job-file.fio
Copy

Check the size of the volumes on the Lightbits node:

Bash
    
 
lbcli list volumes -o json
Copy

You should see that the volume with compression has less physical space used than the volume without compression.

Last updated on

Was this page helpful?