Lots of fastmap writes

[Rickard x Andersson]

Hi,

I have a system running Linux 5.10 which logs quite a lot to a database. 
The system has been running OK since before Christmas but now it usually 
fails after a few hours with errors like these:

May  6 22:29:58 172.26.203.90   warning ubi2 warning: ubi_io_read: error 
-74 (ECC error) while reading 58 bytes from PEB 1:230872, read only 58 
bytes, retry
May  7 00:11:08 172.26.203.90   warning ubi2 warning: ubi_io_read: error 
-74 (ECC error) while reading 58 bytes from PEB 40:239752, read only 58 
bytes, retry
May  7 00:11:08 172.26.203.90   err     ubi2 error: ubi_io_read: error 
-74 (ECC error) while reading 58 bytes from PEB 40:239752, read 58 bytes

Fastmap is used on this system. The ECC errors are usually in the 
fastmap area, erase blocks 0- 63.

When looking more closely at the erase counters they look something like 
this:

0 - 63: 29600
64 - 2043: 2200

It seems like 30 % of the writes are writes to the fastmap area. Any 
ideas of what can cause this many writes to the fastmap area? Heavy load?

Any ideas are welcome.

nand: device found, Manufacturer ID: 0x98, Chip ID: 0xdc
nand: Toshiba TC58NVG2S0H 4G 3.3V 8-bit
nand: 512 MiB, SLC, erase size: 256 KiB, page size: 4096, OOB size: 256
nand: 2 chips detected

UBIFS (ubi2:0): Mounting in authenticated mode
UBIFS (ubi2:0): background thread "ubifs_bgt2_0" started, PID 187
UBIFS (ubi2:0): UBIFS: mounted UBI device 2, volume 0, name "data_volume"
UBIFS (ubi2:0): LEB size: 253952 bytes (248 KiB), min./max. I/O unit 
sizes: 4096 bytes/4096 bytes
UBIFS (ubi2:0): FS size: 505110528 bytes (481 MiB, 1989 LEBs), journal 
size 25395200 bytes (24 MiB, 100 LEBs)
UBIFS (ubi2:0): reserved for root: 4676575 bytes (4566 KiB)
UBIFS (ubi2:0): media format: w5/r0 (latest is w5/r0), UUID 
990A460D-A55E-4B58-ACAD-01FEBC7AF839, small LPT model

ubi2: default fastmap pool size: 100
ubi2: default fastmap WL pool size: 50
ubi2: attaching mtd5
ubi2: attached by fastmap
ubi2: fastmap pool size: 100
ubi2: fastmap WL pool size: 50
ubi2: attached mtd5 (name "data", size 512 MiB)
ubi2: PEB size: 262144 bytes (256 KiB), LEB size: 253952 bytes
ubi2: min./max. I/O unit sizes: 4096/4096, sub-page size 4096
ubi2: VID header offset: 4096 (aligned 4096), data offset: 8192
ubi2: good PEBs: 2040, bad PEBs: 8, corrupted PEBs: 0
ubi2: user volume: 1, internal volumes: 1, max. volumes count: 128
ubi2: max/mean erase counter: 29685/3107, WL threshold: 4096, image 
sequence number: 4060280209
ubi2: available PEBs: 0, total reserved PEBs: 2040, PEBs reserved for 
bad PEB handling: 32
ubi2: background thread "ubi_bgt2d" started, PID 186

Best regards,
Rickard Andersson