Mysql server optimization - how to understand the utility's recommendations?

Question

MySQL

Sorry for the poor knowledge of the topic. I want to delve into mysql optimization. I downloaded the utility, help me understand the recommendations.

-------- Log file Recommendations ------------------------------------------------------------------
[--] Log file: /var/log/mysql/error.log(0B)
[!!] Log file /var/log/mysql/error.log doesn't exist
[!!] Log file /var/log/mysql/error.log isn't readable.

The same log file has 3 values, the second says that the file does not exist, although it exists, it is not clear.
Well, there's not much else I can understand. The mysql server is installed on Ubuntu, everything is by default. I would be grateful for an explanation.

-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +ARCHIVE +BLACKHOLE +CSV -FEDERATED +InnoDB +MEMORY +MRG_MYISAM +MyISAM +PERFORMANCE_SCHEMA
[--] Data in InnoDB tables: 448K (Tables: 21)
[OK] Total fragmented tables: 0

-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[!!] There is no basic password file list!

-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined

-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 3h 6m 38s (34 q [0.003 qps], 17 conn, TX: 47K, RX: 3K)
[--] Reads / Writes: 100% / 0%
[--] Binary logging is disabled
[--] Physical Memory     : 992.2M
[--] Max MySQL memory    : 352.4M
[--] Other process memory: 310.1M
[--] Total buffers: 192.0M global + 1.1M per thread (151 max threads)
[--] P_S Max memory usage: 72B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 193.1M (19.46% of installed RAM)
[OK] Maximum possible memory usage: 352.4M (35.52% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (0/34)
[OK] Highest usage of available connections: 0% (1/151)
[!!] Aborted connections: 11.76%  (2/17)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[!!] Query cache may be disabled by default due to mutex contention.
[!!] Query cache efficiency: 0.0% (0 cached / 11 selects)
[OK] Query cache prunes per day: 0
[OK] No Sort requiring temporary tables
[OK] No joins without indexes
[OK] Temporary tables created on disk: 15% (10 on disk / 66 total)
[OK] Thread cache hit rate: 94% (1 created / 17 connections)
[OK] Table cache hit rate: 28% (33 open / 114 opened)
[OK] Open file limit used: 0% (6/1K)
[OK] Table locks acquired immediately: 100% (102 immediate / 102 locks)

-------- Performance schema ------------------------------------------------------------------------
[--] Memory used by P_S: 72B
[--] Sys schema is installed.

-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is disabled.

-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (3M used / 16M cache)
[OK] Key buffer size / total MyISAM indexes: 16.0M/43.0K
[!!] Read Key buffer hit rate: 50.0% (6 cached / 3 reads)

-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 128.0M/448.0K
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (75 %): 48.0M * 2/128.0M should be equal 25%
[OK] InnoDB buffer pool instances: 1
[--] Number of InnoDB Buffer Pool Chunk : 1 for 1 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[!!] InnoDB Read buffer efficiency: 80.93% (1290 hits/ 1594 total)
[!!] InnoDB Write Log efficiency: 0% (2 hits/ 0 total)
[OK] InnoDB log waits: 0.00% (0 waits / 2 writes)

-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is disabled.

-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.

-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.

-------- RocksDB Metrics ---------------------------------------------------------------------------
[--] RocksDB is disabled.

-------- Spider Metrics ----------------------------------------------------------------------------
[--] Spider is disabled.

-------- Connect Metrics ---------------------------------------------------------------------------
[--] Connect is disabled.

-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.

-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] This is a standalone server.

-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
    MySQL started within last 24 hours - recommendations may be inaccurate
    Reduce or eliminate unclosed connections and network issues
    Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
Variables to adjust:
    query_cache_size (=0)
    query_cache_type (=0)
    query_cache_limit (> 1M, or use smaller result sets)
    innodb_log_file_size * innodb_log_files_in_group should be equals to 1/4 of buffer pool size (=64M) if possible.

Answer 1

it is enough to execute only in Recommendations , and then, grandma in two , I
recommend running the utility after a month of work, continuous, with a load