You need to work through your log and solve the problems showing up:
Jul 15 17:20:00 Tower root: Fix Common Problems Version 2018.06.21
Jul 15 17:20:02 Tower root: Fix Common Problems: Error: Docker application plex has volumes being passed that are mounted by Unassigned Devices, but they are not mounted with the slave option ** Ignored
Jul 15 17:26:10 Tower kernel: ata7.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Jul 15 17:26:10 Tower kernel: ata7.00: failed command: SMART
Jul 15 17:26:10 Tower kernel: ata7.00: cmd b0/d0:01:00:4f:c2/00:00:00:00:00/00 tag 15 pio 512 in
Jul 15 17:26:10 Tower kernel: res 40/00:ff:00:00:00/00:00:00:00:00/40 Emask 0x4 (timeout)
Jul 15 17:26:10 Tower kernel: ata7.00: status: { DRDY }
Jul 15 17:26:10 Tower kernel: ata7: hard resetting link
Jul 15 17:26:10 Tower kernel: ata7: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
Jul 15 17:26:10 Tower kernel: ata7.00: configured for UDMA/133
Jul 15 17:26:10 Tower kernel: ata7: EH complete
Jul 15 17:31:02 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 17:42:04 Tower kernel: ata10.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Jul 15 17:42:04 Tower kernel: ata10.00: failed command: SMART
Jul 15 17:42:04 Tower kernel: ata10.00: cmd b0/d1:01:01:4f:c2/00:00:00:00:00/00 tag 24 pio 512 in
Jul 15 17:42:04 Tower kernel: res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
Jul 15 17:42:04 Tower kernel: ata10.00: status: { DRDY }
Jul 15 17:42:04 Tower kernel: ata10: hard resetting link
Jul 15 17:42:05 Tower kernel: ata10: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Jul 15 17:42:05 Tower kernel: ata10.00: configured for UDMA/133
Jul 15 17:42:05 Tower kernel: ata10: EH complete
Jul 15 17:43:06 Tower kernel: ata10.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Jul 15 17:43:06 Tower kernel: ata10.00: failed command: IDENTIFY DEVICE
Jul 15 17:43:06 Tower kernel: ata10.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 11 pio 512 in
Jul 15 17:43:06 Tower kernel: res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
Jul 15 17:43:06 Tower kernel: ata10.00: status: { DRDY }
Jul 15 17:43:06 Tower kernel: ata10: hard resetting link
Jul 15 17:43:06 Tower kernel: ata10: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Jul 15 17:43:06 Tower kernel: ata10.00: configured for UDMA/133
Jul 15 17:43:06 Tower kernel: ata10: EH complete
Jul 15 17:46:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 17:51:43 Tower emhttpd: shcmd (192): /usr/sbin/hdparm -y /dev/sdb
Jul 15 20:20:02 Tower kernel: ata8.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Jul 15 20:20:02 Tower kernel: ata8.00: failed command: IDENTIFY DEVICE
Jul 15 20:20:02 Tower kernel: ata8.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 11 pio 512 in
Jul 15 20:20:02 Tower kernel: res 40/00:00:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
Jul 15 20:20:02 Tower kernel: ata8.00: status: { DRDY }
Jul 15 20:20:02 Tower kernel: ata8: hard resetting link
Jul 15 20:20:03 Tower kernel: ata8: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Jul 15 20:20:03 Tower kernel: ata8.00: configured for UDMA/100
Jul 15 20:20:03 Tower kernel: ata8: EH complete
Jul 15 20:21:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 20:21:04 Tower kernel: ata8.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
Jul 15 20:21:04 Tower kernel: ata8.00: failed command: IDENTIFY DEVICE
Jul 15 20:21:04 Tower kernel: ata8.00: cmd ec/00:01:00:00:00/00:00:00:00:00/00 tag 2 pio 512 in
Jul 15 20:21:04 Tower kernel: res 40/00:01:01:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
Jul 15 20:21:04 Tower kernel: ata8.00: status: { DRDY }
Jul 15 20:21:04 Tower kernel: ata8: hard resetting link
Jul 15 20:21:04 Tower kernel: ata8: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Jul 15 20:21:04 Tower kernel: ata8.00: configured for UDMA/100
Jul 15 20:21:04 Tower kernel: ata8: EH complete
Jul 15 21:23:11 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 21:39:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 21:54:11 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 22:10:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 22:26:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 22:42:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 22:58:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 15 23:14:01 Tower crond[1589]: ignoring /var/spool/cron/crontabs/root- (non-existent user)
Jul 22 04:25:58 Tower kernel: sdh: detected capacity change from 320072933376 to 0
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208492, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208493, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208494, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208495, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208496, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208497, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208498, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208499, lost async page write
Jul 22 04:25:58 Tower kernel: Buffer I/O error on dev sdh1, logical block 64208500, lost async page write
Jul 22 04:25:58 Tower kernel: sd 7:0:0:0: [sdh] tag#3 UNKNOWN(0x2003) Result: hostbyte=0x04 driverbyte=0x00
Jul 22 04:25:58 Tower kernel: sd 7:0:0:0: [sdh] tag#3 CDB: opcode=0x35 35 00 00 00 00 00 00 00 00 00
Jul 22 04:25:58 Tower kernel: print_req_error: I/O error, dev sdh, sector 65744
Jul 22 04:25:58 Tower kernel: REISERFS abort (device sdh1): Journal write error in flush_commit_list
Jul 22 04:25:58 Tower kernel: REISERFS warning (device sdh1): journal-837 _update_journal_header_block: IO error during journal replay
Jul 22 04:25:58 Tower kernel: print_req_error: I/O error, dev loop2, sector 25480
Jul 22 04:25:58 Tower kernel: BTRFS error (device loop2): bdev /dev/loop2 errs: wr 0, rd 1, flush 0, corrupt 0, gen 0
It goes on and on. I would start by solving the disk issues.