zram setup

Deployment

apt install zram-tools

nano /etc/default/zramswap

ALGO=lz4 #low cpu overhead
or ALGO=zstd #high compress ratio high cpu overhead
PERCENT=50  #fifty percent of total ram size for zram

enable zram service

systemctl enable --now zramswap

sudo systemctl restart zramswap

check the zram status

zramctl  

swapon --show

LZ4 (default / fastest)

lz4
lz4hc

Mode	Speed	Compression	CPU cost	zram suitability
lz4	⭐⭐⭐⭐⭐	⭐⭐	⭐	✅ Excellent
lz4hc	⭐⭐⭐	⭐⭐⭐	⭐⭐	⚠️ Rarely worth it

lz4

• Extremely fast compression and decompression
• Low CPU overhead
• Best choice for swap-on-zram and low-power CPUs

lz4hc (high compression)

• Slightly better compression
• Much slower compression
• Usually not recommended for zram

Level	Speed	Compression	CPU cost	zram use case
zstd:1	⭐⭐⭐⭐	⭐⭐⭐	⭐⭐	✅ Good balance
zstd:3	⭐⭐⭐	⭐⭐⭐⭐	⭐⭐⭐	⚠️ Maybe
zstd:6	⭐⭐	⭐⭐⭐⭐⭐	⭐⭐⭐⭐	❌ Not ideal
zstd:10+	⭐	⭐⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	❌ No

use zstd:1 or zstd:3

• Anything higher is usually wasted CPU.

Aspect	LZ4	ZSTD
Compression speed	⭐⭐⭐⭐⭐	⭐⭐⭐
Decompression speed	⭐⭐⭐⭐⭐	⭐⭐⭐⭐
Compression ratio	⭐⭐	⭐⭐⭐⭐
CPU usage	⭐	⭐⭐⭐
Swap latency	⭐⭐⭐⭐⭐	⭐⭐⭐
Low-end CPU	✅ Perfect	⚠️ Maybe