Being a Story of Databases, Binary Logs, WAL Recordsdata, and the Redemption of Ebenezer Scrooge, DBA
Half the First — In Which We Meet Ebenezer Scrooge, Database Administrator Extraordinary
It was a chilly, darkish, and CPU-bound night time. The wind blew fierce throughout the datacenter racks, and the disks did rattle of their trays like bones. Ebenezer Scrooge, Senior Database Administrator (Degree III, self-certified), sat hunched o’er his terminal, lit solely by the ghostly glow of Vim. He was a person of bytes and bits, parsimonious together with his time, and proud — oh, so proud! — of by no means as soon as taking a backup.
He refused to put money into correct backup options, believing that “databases are supposed to be stay, not backed up.” His servers have been previous, his storage was restricted, and his catastrophe restoration plans have been non-existent.
“Backups?” quoth Scrooge. “Bah! WAL-humbug! Actual males make no backups, and if the information be misplaced, ‘tis however the consumer’s fault for querying unwise.”
His junior assistant, younger Cratchit — a timid lad who stored his .pgpass neat, his /and so on/mysql/my.cnf curated like scripture, his pg_basebackup cronjob tidy, and his xtrabackup schedules tidier nonetheless — dared whisper with the warning of a person who had seen replication break within the night time:
“Sir… ought to we not take a look at the Level-in-Time Restoration procedures — each PostgreSQL and MySQL — afore we belief them in manufacturing? For WALs and binlogs alike should show their price within the hour of calamity.”
Scrooge scowled, turning upon him the total radiance of a person sure of his personal immortality.
“PITR? BINLOG REPLAY? I’ve no time for such phantasms! I tune autovacuum! I optimize InnoDB buffer swimming pools! I’m grasp of checkpoints and vacuum freeze, of redo logs and doublewrite buffers! My databases are everlasting!”
He rose, pacing the room with rising vanity.
“Why ought to I take a look at restoring a PostgreSQL cluster when my WAL archiver by no means fails? Why ought to I follow restoring MySQL when my GTIDs circulation pure and my replicas lag not? Backups are the indulgence of cowards — however I’m Scrooge! I’ve uptime! I’ve replicas! I’ve religion!”
Cratchit swallowed arduous, for he had heard such boasts earlier than from DBAs now lengthy vanished from the occupation.
And so saying, Scrooge closed his laptop computer, muttering curses towards backup scripts and S3 buckets, and went house to his lonely flat, the place even systemctl feared to run.
Half the Second — The Ghost of Backups Previous
That night time, as Scrooge lay in mattress surrounded by chilly, blinking router lights, there got here a sound — clink-clank-clunk, just like the weary drive heads searching for throughout historical HDD platters, trying to find sectors lengthy forgotten. A spectral determine emerged, its type woven of compressed database components and binary log archives, trailing a protracted chain of WAL recordsdata that scraped throughout the ground like steel on stone.
“Who artwork thou?” cried Scrooge, clutching his pillow like a frightened sysadmin clutching an unmounted quantity.
“I’m the Ghost of Backups Previous,” mentioned the determine, “and these are the chains I made when thou didst disable cron. Behold!”
The room shimmered, and so they discovered themselves within the server room of yore – buzzing, orderly, and bathed within the pale glow of console displays. There, a youthful Scrooge bent over his keyboard with cautious devotion, tending to his engines as a shepherd tends his flock.
On one terminal, he issued:
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pg_basebackup –D /mnt/backup –Ft –z |
The output shone shiny and inexperienced, on one other display, with out hesitation, he invoked:
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xtrabackup —backup —goal–dir=/backups/full_2025–12–24 |
The logs rolled by, regular and reassuring, the backup chain complete and sound.
“Behold, Ebenezer,” mentioned the spirit. “In these days thou didst honor each thy databases alike. Thou didst backup each file, take a look at each restore, and belief neither WAL nor binlog till they proved themselves upon a staging host. Thy customers slept peacefully, guarded by the redundancy of thy diligence.”
However the imaginative and prescient dimmed.
The youthful Scrooge straightened, delight creeping throughout his face like shadow over a failing disk.
“Backups gradual the system,” he declared. “Sizzling backups are for the faint of coronary heart. Replication alone shall be my protect.”
Without delay, the WALs withered, the bottom backup collapsed into mud, the binlog chain broke like a brittle hyperlink, and metadata evaporated into the stale air of the deserted server room.
The spirit’s voice trembled.
“Mark my phrases, Ebenezer: when the muse is forged apart, the WALs of the current discover no place to land, nor the binlogs any second from which to start. Replication will not be salvation — for corruption replicates sooner than reality. Overlook this lesson, and all shall be misplaced.”
Because the ghost dissolved into swirling TAR fragments and drifting binary mud, Scrooge heard a fading refrain:
“the tough cry of rsync failing with exit code 12…”
and beneath it, a whisper as smooth as a misplaced packet on the wire:
“put together your backups… put together your backups…”
Half the Third — The Ghost of Logs Current
Scrooge awoke on the stroke of midnight to see a mighty specter clad within the inexperienced robes of pg_wal. Round his waist hung a belt of flashing GTIDs, and from his arms streamed an limitless scroll of WALs, half bathed in golden MySQL binlogs.
“I’m the Ghost of LOGS Current,” he boomed. “Come, Ebenezer! See how thy database but breathes, because of mine steady write-ahead redemption!”
They flew via the night time to the manufacturing host. There, diligent Cratchit tended the WAL archives and binary logs like a shepherd, making certain that archive_command returned true, checked the duplicate lag with care, and that the S3 bucket overflowed not.
“These logs,” mentioned the Ghost, “document each humble INSERT, each noble COMMIT. With out them, no restoration to any level might be performed.”
Scrooge gazed in awe because the spirit waved his arm. The GTIDs and LSNs flowed like a river of time, and the Ghost did cry:
“See, Ebenezer! Level in Time Restoration — the miracle of moments restored!”
He confirmed him how restore_command and recovery_target_time would possibly summon a fallen PostgreSQL cluster from the ashes, restoring it to the very heartbeat earlier than catastrophe struck; and the way, within the realm of MySQL, the cautious invocation of mysqlbinlog, guided by one’s chosen stop-datetime, might weave binlog occasions anew, re-creating the world because it was earlier than calamity descended.
Scrooge trembled, whispering:
“’Tis sorcery… nay, not sorcery in any respect — ’tis however PostgreSQL and MySQL, every wielding its personal sacred logs to show again the tide of damage.”
However as he seemed nearer, the WALs started to falter. The S3 bucket dried up. The binary logs ceased to seem. The ghost’s gown dimmed.
“My time grows quick,” mentioned the spirit. “With out backups, my work is naught. When the bottom backup is gone, I’ve no origin to replay upon. With out logs, I can’t reconstruct thy transactions. Your Current is doomed if the Previous is misplaced.”
And the Ghost of LOGS Current light, leaving solely a faint echo:
“Maintain thine archives protected, and thy database shall stay once more.”
Half the Fourth — The Ghost of Backups But to Come
The clock struck one, and all of the blinking LEDs in Scrooge’s flat fell darkish. A silence heavier than fsync delay stuffed the air. A shadow fell upon the room. The temperature dropped, and the blinking lights of the routers dimmed to a ghostly flicker. From the darkness emerged a towering determine, its type shrouded in thriller, clad in tattered remnants of corrupted knowledge recordsdata and damaged replication chains.
“Artwork thou… the Ghost of Backups But to Come?” quavered Scrooge.
The determine nodded solemnly, its eyes glowing with an eerie gentle. In a single hand, it held a shattered PostgreSQL cluster, its recordsdata corrupted past restore. Within the different, a ruined MySQL occasion, its InnoDB tablespaces mangled and unreadable.
“Good heavens!” cried Scrooge. “The place are the preliminary backups? The place are the archived WALs? The place are the binary logs?”
The spirit pointed to a crumbling drive within the nook, its SMART standing failed, its RAID array degraded, its S3 credentials expired three years therefore.
“Certainly,” pleaded Scrooge, “I can restore from my replicas!”
The phantom turned, and earlier than them lay a smoking damage of replication errors:
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Last_SQL_Errno: 1236 Last_SQL_Error: Reproduction has failed to open the relay log file |
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2025–12–25 00:00:00.000 UTC [28] FATAL: might not obtain knowledge from WAL stream: ERROR: requested WAL phase 00000001000000000000000A has already been eliminated |
The ghost pointed to a lonely electronic mail from administration:
“We remorse to tell you that the manufacturing databases have been misplaced. We hope the memes have been price it.”
The builders wept. The CEO paced the corridor. The CFO fainted upon listening to that no snapshot, no backup, no duplicate might be restored.
Scrooge fell to his knees, clutching on the hem of the phantom’s gown.
“Spirit! I see it now! A database with out backups is however a citadel constructed on unstable storage! I shall change! I shall again up hourly, take a look at weekly, and monitor the archiver! I’ll use xtrabackup and pgBackRest and confirm each restore!”
At this, the phantom’s hood fell again — and beneath it, Scrooge noticed not a cranium, however an empty listing: /mnt/backup. He screamed — and awoke.
Half the Fifth — In Which Scrooge is Restored
Morning daylight streamed throughout his desk, reflecting off his espresso mug that learn “Actual DBAs Make No Backups”. With trembling arms, Scrooge seized it and forged it into the bin.
“No extra!” he cried. “This present day I shall provoke a worldwide backup technique, and verily shall I archive each binlogs and WALs with self-discipline!”
He dashed to his workstation, his fingers flying throughout the keyboard like angels upon the harp of restoration. Then he edited configuration recordsdata with trembling reverence.
And he added cronjobs, aye, blessed cronjobs, that the ghosts of Backups Previous and WALs Current would possibly smile upon him forevermore.
That night, Scrooge did summon younger Cratchit and spake thus:
“My boy, from at the present time forth, thou shalt confirm each backup, thou shalt take a look at the PITR procedures quarterly, and thou shalt preserve secondaries in heat standby. Right here — take this pgBackRest configuration, and thoughts thou set the retention coverage!”
Cratchit wept for pleasure.
And the customers rejoiced, for his or her queries not feared corruption, nor downtime, nor the wrath of misplaced log segments. The databases lived once more, restored to a degree in time of righteousness and consistency.
And it was mentioned from that day ahead, in each knowledge heart and cloud area, that there was no DBA extra vigilant, nor database safer, than previous Ebenezer Scrooge, who had discovered ultimately the gospel of Database Level In Time Restoration.
He spoke usually to the following era:
“Youngsters, replication will not be a backup. Backups are a backup. And a examined restore is the one backup that actually exists.”
And it was mentioned that no cluster underneath Scrooge was ever misplaced once more, for each WAL and binlog smiled upon him.
In regards to the Creator
Pep PlaPep has been working with databases all his life. Born in a small village by the Mediterranean, he at present lives in Barcelona. He loves tech, touring, good meals, music and, all issues NASA. He hates speaking about himself within the third individual and has a selected humorousness. Fortunately married, he’s the daddy of three boys and three cats.
