Hey everyone, hoping to tap into the collective wisdom here! 🚀
I'm currently involved in evaluating a few cloud data warehousing and analytics platforms (think BigQuery, Redshift, Snowflake, etc.), and I keep hitting a wall when it comes to their **data deletion and retention processes**. The sales demos are all about ingestion speed, query performance, and shiny features. But when I ask, "Okay, but when I delete a dataset or drop a table, what *actually* happens? How long before it's truly gone from your backups or underlying storage?" – things get vague real fast.
I get generic answers like "We follow industry best practices" or "Data is removed in accordance with our policy." That's not good enough for our compliance needs (GDPR, specifically). I need concrete, documented steps and timelines.
Has anyone else fought this battle and come out with a usable template or a set of questions that forces vendors to be specific? I'm thinking of building an evaluation rubric section just for this. Something with clear criteria, for example:
* **Immediate Deletion Process:** Does the `DROP TABLE` command trigger an immediate soft delete, and what's the interface/API to then purge it?
* **Backup & Disaster Recovery Retention:** Are deleted objects pruned from nightly backups? If so, what's the SLA (e.g., "removed from backups within 30 days")?
* **Audit Trail:** Can they provide an audit log proving the final purging event?
* **Contractual Language:** Is the exact process and timeline specified in the Data Processing Agreement (DPA) or is it just a fluffy policy doc?
I'd love to see any RFP clauses or demo evaluation checklists you've used successfully to nail this down. Maybe we can crowdsource a solid set of requirements.
I can share the Terraform module I use to spin up test environments for these platforms if that's helpful—makes it easier to test their deletion claims in a sandbox! Let me know.
~CloudOps
Infrastructure as code is the only way
Oh man, you're hitting on the worst part of vendor evaluations. That "industry best practices" line is a red flag for me, too. It usually means they haven't documented the actual process for customers.
Your rubric idea is solid. For GDPR, you need a verifiable chain of custody. I'd push for their backup and disaster recovery specifics - how backups are scoped, their retention period, and if a `DROP` action triggers a logical delete in the backup system or if it's a full image they keep. The timeline for purge from backups is often the critical gap.
One thing I've done is ask them to point me to the exact support doc or internal runbook that an engineer would follow if a customer submitted a formal erasure request. If they can't, they're likely winging it.
Your rubric approach is exactly the direction to go. Push beyond the logical delete in the primary store; the real crux is the backup and replication systems. Many platforms treat backups as immutable snapshots for a fixed period, rendering a `DROP TABLE` operation completely irrelevant to those stored bytes.
I'd add a specific criterion: "Documented, time-bound process for purging data from all backup and disaster recovery systems." Request their internal ticket flow for a right-to-erasure request. If they can't produce it, they don't have an engineered solution, just a policy aspiration.
Also, ask about any underlying object storage layer (e.g., S3, GCS) and whether "delete" commands propagate as bucket-level version deletions or just a marker. The data persistence in versioned storage is a common compliance blind spot.
Absolutely. Your rubric idea is critical. Building on your **Immediate Deletion Process** point, I'd suggest splitting it into two distinct criteria: one for the control plane and one for the data plane.
* **Logical/Control Plane Deletion:** When you issue a `DROP TABLE`, does the metadata (table name, schema, column definitions) become immediately unreachable and marked for purge? Or does it linger in a system catalog, recoverable via an `UNDROP` command, for a vendor-defined period? This has GDPR implications.
* **Physical/Data Plane Deletion:** The actual bytes. Does the command trigger an asynchronous process to delete underlying files in object storage (e.g., Parquet files in S3), or does it merely revoke your access pointer? This is where you need to ask about the garbage collection cycle - is it minutes, hours, or days? They should have a metric for this.
Your request for the interface/API to then purge is key. Ask if they expose a `PURGE` command or similar that forces a garbage collection, or if the process is entirely opaque and on their backend schedule. Snowflake's TIME_TRAVEL and PURGE features, for example, are documented and explicit, which is what you should demand from all of them.
Data is the source of truth.
Good call on the rubric. Your "Immediate Deletion Process" section is the right starting point, but you need to define "immediate" in terms of seconds vs hours. Push for their service-level objective (SLO) for when the purge job runs after a drop command.
For the backup question, don't ask for policy. Ask to see the runbook for a `GDPR Article 17` erasure request. If they say it's internal, that's your answer - they don't have a real process.
I'd add a technical validation step to your rubric: can they provide a log event or API response with a deletion token or manifest that lists the specific storage objects (file IDs, block IDs) scheduled for deletion? Without that, you can't audit it.
Numbers don't lie
Oh, asking for the actual runbook is such a clever angle. I would have never thought to ask for that directly, I probably would have just accepted a policy doc. The idea of a deletion token or manifest is really interesting, too. It sounds like that's the only way you could ever prove it was done.
A follow-up maybe: is it unrealistic to expect vendors to actually hand over that runbook? Couldn't they just say it's part of their confidential security procedures? I'm trying to figure out how hard to push on that point.
The SLO ask is critical, but you have to be ready for the cost implication. A "one-hour SLO for physical byte deletion" is a very expensive engineering promise. If they actually commit to that, expect your compute/scan costs to be higher because it requires immediate, aggressive background processing. Most platforms won't give you that number because they don't want to guarantee it.
And yes, they'll absolutely refuse to share the internal runbook. That's your signal. A mature vendor should have a *customer-facing* version of that process, stripped of internal IP, that outlines triggers, steps, and verification. If they can't produce that, they're telling you it's ad-hoc.
cost optimization, not cost cutting