1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
Dismiss Notice

Welcome To SNBForums

SNBForums is a community for anyone who wants to learn about or discuss the latest in wireless routers, network storage and the ins and outs of building and maintaining a small network.

If you'd like to post a question, simply register and have at it!

While you're at it, please check out SmallNetBuilder for product reviews and our famous Router Charts, Ranker and plenty more!

New AC86U - Bad PEB, a problem?

Discussion in 'ASUS AC / AX Routers & Adapters' started by Dfects, Oct 8, 2018.

  1. Dfects

    Dfects Occasional Visitor

    Joined:
    Feb 25, 2015
    Messages:
    23
    I've just been playing with my new AC86U, everything seems to be working okay but noticed in the logs it reports a bad physical erase block:

    Code:
    May  5 06:05:05 kernel: ubi0: good PEBs: 724, bad PEBs: 1, corrupted PEBs: 0
    Earlier log entries on reboot have been fine.

    Is this something to worry about?
     
  2. Please support SNBForums! Just click on this link before you buy something from Amazon and we'll get a small commission on anything you buy. Thanks!
  3. OzarkEdge

    OzarkEdge Very Senior Member

    Joined:
    Feb 14, 2018
    Messages:
    695
    Location:
    USA
    I don't know! But I checked my 86U syslog... no bad PEBs here but I noticed this: PEBs reserved for bad PEB handling: 4.

    So, maybe they expect a few bad PEBs... if so, maybe you are down to 3 in reserve. :)

    OE
     
  4. Dfects

    Dfects Occasional Visitor

    Joined:
    Feb 25, 2015
    Messages:
    23
    I think there are two different chips or partitions... one has 64 peb's with 4 reserved for errors (ubi1) and the one I listed (ubi0) has 725 normally with 15 in reserve... mine being on 724/14 now.
     
  5. OzarkEdge

    OzarkEdge Very Senior Member

    Joined:
    Feb 14, 2018
    Messages:
    695
    Location:
    USA
    I have no ubi0 entries here. h/w 1.5

    OE
     
  6. Grisu

    Grisu Very Senior Member

    Joined:
    Aug 28, 2014
    Messages:
    1,195
    only for reference my values:
    Oct 7 23:24:27 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    Oct 7 23:24:27 kernel: ubi1: user volume: 1, internal volumes: 1, max. volumes count: 128
    Oct 7 23:24:27 kernel: ubi1: max/mean erase counter: 3/2, WL threshold: 4096, image sequence number: 1960956644
    Oct 7 23:24:27 kernel: ubi1: available PEBs: 0, total reserved PEBs: 64, PEBs reserved for bad PEB handling: 4

    Could not find ubi0 too.
     
  7. Dfects

    Dfects Occasional Visitor

    Joined:
    Feb 25, 2015
    Messages:
    23
    Interesting. Not sure if it only logs it on reboot. Searching the logs for "bad pebs:" I get:

    Code:
    May  5 06:05:05 kernel: ubi0: good PEBs: 724, bad PEBs: 1, corrupted PEBs: 0
    May  5 06:05:05 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    May  5 06:05:05 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    May  5 06:05:11 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    Oct  8 13:36:38 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    Oct  8 13:36:41 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    Oct  8 13:36:54 kernel: ubi1: good PEBs: 64, bad PEBs: 0, corrupted PEBs: 0
    These are all after clearing the log and rebooting.
     
  8. CrashXRu

    CrashXRu Occasional Visitor

    Joined:
    Oct 6, 2018
    Messages:
    10
    Location:
    Russia / Siberia
    dmesg | grep -e "flash" -e "nand"

    check bad block
     
  9. Grisu

    Grisu Very Senior Member

    Joined:
    Aug 28, 2014
    Messages:
    1,195
    seems to exist only on reboot, timestamp May 5th after I loaded Merlin 384_7.

    May 5 07:05:06 kernel: ubi0: volume 0 ("rootfs_ubifs") re-sized from 566 to 706 LEBs
    May 5 07:05:06 kernel: ubi0: attached mtd0 (name "rootfs", size 90 MiB)
    May 5 07:05:06 kernel: ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 126976 bytes
    May 5 07:05:06 kernel: ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 2048
    May 5 07:05:06 kernel: ubi0: VID header offset: 2048 (aligned 2048), data offset: 4096
    May 5 07:05:06 kernel: ubi0: good PEBs: 725, bad PEBs: 0, corrupted PEBs: 0
    May 5 07:05:06 kernel: ubi0: user volume: 1, internal volumes: 1, max. volumes count: 128
    May 5 07:05:06 kernel: ubi0: max/mean erase counter: 1/0, WL threshold: 4096, image sequence number: 0
    May 5 07:05:06 kernel: ubi0: available PEBs: 0, total reserved PEBs: 725, PEBs reserved for bad PEB handling: 15
    May 5 07:05:06 kernel: ubi0: background thread "ubi_bgt0d" started, PID 60
     
  10. Grisu

    Grisu Very Senior Member

    Joined:
    Aug 28, 2014
    Messages:
    1,195
    get this red line with "dmesg" only:
    [ERROR pktrunner] runnerUcast_inet6addr_event,202: Could not rdpa_ucast_ipv6_host_address_table_find
     
  11. Dfects

    Dfects Occasional Visitor

    Joined:
    Feb 25, 2015
    Messages:
    23
    I'll try that later too... pretty sure that flash chip has a bad block though on my router. From my understanding, bad blocks can happen during the manufacturing process and isn't a sign that the chip itself is going to fail sooner? Guessing most manufacturers have tolerances for this kind of thing.

    If anyone can chime in and tell me if my understanding is correct or if I should be requesting a replacement i'd appreciate it :)
     
  12. Grisu

    Grisu Very Senior Member

    Joined:
    Aug 28, 2014
    Messages:
    1,195
    same as a pixel failure on LCD-screens, long time there has been allowed to be some without return.

    Thats why they calculated some spare, no need or reason for a return.

    I only dont know the difference or what exactly meant with bad and corrupted (maybe caused by my bad English).
     
    Dfects likes this.
Please support SNBForums! Just click on this link before you buy something from Amazon and we'll get a small commission on anything you buy. Thanks!