Question about time to sync after using FASTSYNC and machine specifications needed

[fedex1]

Hi, we installed a btcpayserver in the cloud. It is not a very big machine.
The question is what is the required machine for btcpayserver to be usable?

Can someone tell us why the last 5% seems to take forever?

We have

CURRENT STATS IT APPEARS TO BE OKAY

root@btcpaymain-vm:~# docker stats --no-stream 
CONTAINER ID   NAME                                CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
787edc8da811   letsencrypt-nginx-proxy-companion   0.07%     7.035MiB / 3.567GiB   0.19%     288kB / 85.6kB    600MB / 688kB     10
ddf3e3b1fc91   nginx-gen                           0.07%     4.551MiB / 3.567GiB   0.12%     48.7kB / 4.09kB   10.7MB / 24.6kB   6
690852934ee6   generated_btcpayserver_1            0.05%     283.5MiB / 3.567GiB   7.76%     531MB / 25.3MB    3.61GB / 0B       18
66c9c0b7e909   generated_lnd_bitcoin_rtl_1         0.00%     23.61MiB / 3.567GiB   0.65%     49.5kB / 4.09kB   579MB / 0B        12
8a0ae35216b7   nginx                               0.00%     5.766MiB / 3.567GiB   0.16%     15.2MB / 10.2MB   754MB / 4.1kB     2
0c4650adcf05   btcpayserver_lnd_bitcoin            0.10%     1.309MiB / 3.567GiB   0.04%     51.1kB / 4.09kB   66.3MB / 8.19kB   3
99a4eaf8a116   generated_nbxplorer_1               0.07%     92.34MiB / 3.567GiB   2.53%     13.3MB / 12.6MB   1.17GB / 4.1kB    15
6d8a321dd5c3   tor-gen                             0.06%     4.633MiB / 3.567GiB   0.13%     52kB / 4.09kB     23MB / 8.19kB     6
e6dbaafb4477   btcpayserver_bitcoind               1.36%     1.823GiB / 3.567GiB   51.10%    7.19GB / 50.9MB   714GB / 55.1GB    15
4226f3490a4f   tor                                 0.04%     50.73MiB / 3.567GiB   1.39%     1.23GB / 1.14GB   548MB / 260MB     3
baaffa29c3f8   generated_postgres_1                0.02%     35.19MiB / 3.567GiB   0.96%     6.35MB / 2.98MB   6.22GB / 592MB    9

BUT THE BITCOIND log shows that syncing the last 5% is very slow

root@btcpaymain-vm:~# docker logs   btcpayserver_bitcoind |tail
2024-04-01T14:31:48Z New outbound-full-relay v1 peer connected: version: 70016, blocks=837252, peer=3453
2024-04-01T14:32:43Z UpdateTip: new best=000000000000000000007fb7cd875a915b9e9691b73d6445a4b79bf9b3fece87 height=824848 version=0x3fff0000 log2_work=94.652797 tx=949233333 date='2024-01-08T10:38:58Z' progress=0.959416 cache=349.7MiB(2888035txo)
2024-04-01T14:33:23Z UpdateTip: new best=0000000000000000000388f70fceabf46ab0e3865e961de8739a48bf4418e5ea height=824849 version=0x201b2000 log2_work=94.652812 tx=949237641 date='2024-01-08T10:53:48Z' progress=0.959420 cache=350.4MiB(2895016txo)
2024-04-01T14:33:56Z UpdateTip: new best=000000000000000000039c4d1a56ccede78adfe4e85b2b276421d9e453eed93f height=824850 version=0x26a98000 log2_work=94.652826 tx=949241545 date='2024-01-08T10:54:13Z' progress=0.959420 cache=351.1MiB(2900040txo)
2024-04-01T14:34:42Z UpdateTip: new best=00000000000000000002a0c3c691ef7436892b9ef59fde4da1d641bc511fa864 height=824851 version=0x2953e000 log2_work=94.652841 tx=949245670 date='2024-01-08T11:16:58Z' progress=0.959428 cache=351.9MiB(2907424txo)
2024-04-01T14:35:24Z UpdateTip: new best=000000000000000000003e085e9b2941543ace6bd129ffe28708cec86ef2d717 height=824852 version=0x22026000 log2_work=94.652856 tx=949249843 date='2024-01-08T11:22:00Z' progress=0.959429 cache=352.7MiB(2913058txo)
2024-04-01T14:36:22Z UpdateTip: new best=0000000000000000000157ee338df7b343105cebb10fca0a84260ea01a93340f height=824853 version=0x2395a000 log2_work=94.652870 tx=949253420 date='2024-01-08T11:33:47Z' progress=0.959433 cache=353.6MiB(2918251txo)
2024-04-01T14:37:22Z UpdateTip: new best=00000000000000000002404e0b4839c458bd4c723950112ad3c4f8e126b0fefe height=824854 version=0x21090000 log2_work=94.652885 tx=949257193 date='2024-01-08T11:51:24Z' progress=0.959438 cache=354.3MiB(2924776txo)
2024-04-01T14:37:49Z UpdateTip: new best=00000000000000000001dc706df88cd75cbfb31ece8c728d6b00314ab6682ca1 height=824855 version=0x2b770000 log2_work=94.652899 tx=949261391 date='2024-01-08T11:55:05Z' progress=0.959440 cache=355.0MiB(2930611txo)
2024-04-01T14:38:04Z UpdateTip: new best=0000000000000000000382ba33932f60e6fe0b035315b45b81e6dbc111926b4c height=824856 version=0x2f396000 log2_work=94.652914 tx=949266873 date='2024-01-08T11:59:00Z' progress=0.959441 cache=355.6MiB(2933373txo)

This is the machine cpu

root@btcpaymain-vm:~# lscpu 
Architecture:            x86_64
  CPU op-mode(s):        32-bit, 64-bit
  Address sizes:         46 bits physical, 48 bits virtual
  Byte Order:            Little Endian
CPU(s):                  1
  On-line CPU(s) list:   0
Vendor ID:               GenuineIntel
  Model name:            Intel(R) Xeon(R) CPU @ 2.30GHz
    CPU family:          6
    Model:               63
    Thread(s) per core:  1
    Core(s) per socket:  1
    Socket(s):           1
    Stepping:            0
    BogoMIPS:            4599.99
    Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1
                         gb rdtscp lm constant_tsc rep_good nopl xtopology nonstop_tsc cpuid tsc_known_freq pni pclmulqdq ssse3 fma cx16 pcid sse
                         4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm invpcid_single pti ssbd ibrs ibpb stibp 
                         fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt arat md_clear arch_capabilities
Virtualization features: 
  Hypervisor vendor:     KVM
  Virtualization type:   full
Caches (sum of all):     
  L1d:                   32 KiB (1 instance)
  L1i:                   32 KiB (1 instance)
  L2:                    256 KiB (1 instance)
  L3:                    45 MiB (1 instance)
NUMA:                    
  NUMA node(s):          1
  NUMA node0 CPU(s):     0
Vulnerabilities:         
  Gather data sampling:  Not affected
  Itlb multihit:         Not affected
  L1tf:                  Mitigation; PTE Inversion
  Mds:                   Mitigation; Clear CPU buffers; SMT Host state unknown
  Meltdown:              Mitigation; PTI
  Mmio stale data:       Vulnerable: Clear CPU buffers attempted, no microcode; SMT Host state unknown
  Retbleed:              Mitigation; IBRS
  Spec rstack overflow:  Not affected
  Spec store bypass:     Mitigation; Speculative Store Bypass disabled via prctl
  Spectre v1:            Mitigation; usercopy/swapgs barriers and __user pointer sanitization
  Spectre v2:            Mitigation; IBRS, IBPB conditional, STIBP disabled, RSB filling, PBRSB-eIBRS Not affected
  Srbds:                 Not affected
  Tsx async abort:       Not affected