Increase L2ARC write rate and headroom

Current L2ARC write rate and headroom parameters are very conservative:
l2arc_write_max=8M and l2arc_headroom=2 (ie: a full L2ARC writes at
8 MB/s, scanning 16/32 MB of ARC tail each time; a warming L2ARC runs
at 2x these rates).

These values were selected 15+ years ago based on then-current SSDs
size, performance and endurance. Today we have multi-TB, fast and
cheap SSDs which can sustain much higher read/write rates.

For this reason, this patch increases l2arc_write_max to 32M and
l2arc_headroom to 8 (4x increase for both).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Gionatan Danti <g.danti@assyoma.it>
Closes #15457
This commit is contained in:
shodanshok
2023-11-09 01:30:47 +01:00
committed by GitHub
parent 1c1be60fa2
commit 887a3c533b
2 changed files with 5 additions and 5 deletions
+2 -2
View File
@@ -776,8 +776,8 @@ uint64_t zfs_crc64_table[256];
* Level 2 ARC
*/
#define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */
#define L2ARC_HEADROOM 2 /* num of writes */
#define L2ARC_WRITE_SIZE (32 * 1024 * 1024) /* initial write max */
#define L2ARC_HEADROOM 8 /* num of writes */
/*
* If we discover during ARC scan any buffers to be compressed, we boost