Forum ©XSIBackup: ©VMWare ©ESXi Backup Software

[quote=admin]If you connect your [b]©Synology NAS[/b] via NFS or iSCSI, your remote FS is locally available to the ESXi server and backups are a mere local copy. Nonetheless, the fact that you are mounting over a network and via an intermediary protocol makes the setup more complex and thus more prone to errors, just because it comprises more elements than a plain local disk attached to a local controller.

Nevertheless, if everything is working fine you should expect backups to be made normally.

When you start to receive checksum mismatches, that is a sign that something is not working quite well. In case of locally attached disks, you could infere that some physical damage is causing the errors, you should then run some extensive SMART disgnostics to decide whether some of your HDs or SSDs needs to be replaced.

[url=https://33hops.com/xsibackup-disk-checksum-verification-silent-corruption.html]Disk checksum verification explained[/url]

When it comes to NFS and iSCSI, the problem can as well be caused by a faulty disk, but it can also be due to some of the other elements playing a role in remotely mounting the storage volume, such as: cables, switches, NICs, etc...[/quote]

Hi admin,

Thanks for your reply. I post one XSI mail result down here. I was never used to certify backup but I decided it was a good idea when having to backup an administrative software with lots of data. It was then that checksum errors popped up. I added mail servers to that and also (see mail output) I receive sha checksum errors every time backup runs... sometimes the checksum is right (1 over 6). I checked smart my disk with extensive tests, then checked by changing raid1 volume (HGST vs. WD disks).. Now I opened a ticket to Synology and they make me try a memory test which seems to be ok. This is a pretty "enterprise" grade infrastructure: HP DL360 raid1+0 disks --> 10G fiber --> Cisco sg550xg -> 2x 1G bonding ethernet -> Synology (disaster recovery). I'll let you know what comes from Synology support.

Wed Feb 5 05:00:08 UTC 2020
XSIBACKUP-PRO 11.2.2.1 AT HOST:
esxi100.rifnet.local
IP v4: 151.1.254.146/ 255.255.255.0
VMware ESXi 6.0.0 build-5050593

Done hot backup (id: 10) using vmkfstools (no compression)
Backing up to folder /vmfs/volumes/archives/Mail/20200205050005
The backup room has been limited to 1000 Gb.
Available room in device /vmfs/volumes/archives/Mail before backup: 1000 Gb.
Sparse size on disk of the selected virtual machines: 277 Gb.
Needed room in device /vmfs/volumes/archives/Mail for backup: 236 Gb.
(Id)VM Name    State    Size (Gb)    Stop    Copy    Start    Time (min)    Speed (mb/s)
(8) linux-mail-55    ON    181/ 191    NO (hot backup)    sha1 CERTIFIED    -    92    33/ 35
(9) linux-mail-74    ON    55/ 86    NO (hot backup)    KO!    -    37    25/ 39
Last error raised for the above VM:
ERROR CLNCERT0, details: [linux-mail-74] error: sha1 hashes are different [linux-mail-74-flat.vmdk], details: 0
Available space in device /vmfs/volumes/archives/Mail after backup: 765 Gb.
Complete backup elapsed time: 130 min
The ESXi configuration was saved to /vmfs/volumes/archives/Mail/20200205050005