How fast would a Tenser’s Floating Disk descend if I pulled it over a long drop?

So I’m designing a variant human warlock with the wizard ritual caster feat and while considering which rituals to start with I read the description for Tenser’s floating disk and looking through the eldritch invocations I saw the Ascendant step invocation allows levitation on myself at will so if I was to make a floating disk, have a party member or some equipment placed on it and then go down a chasm or hole or off the side of a flying ship/island etc would the disk follow at my levitate speed (20 feet descent or ascent per turn) or my movement speed (30 feet per turn) or would it drop like a rock? I’m picturing using it like a down elevator. Additionally would I be able to hold a wooden tabletop under the disk and levitate up and have it ascend to stay 3 feet above the surface?

For ease of reference here is the description of the relevant spells (quoted from D&D Beyond).

Tenser’s floating disk:

This spell creates a circular, horizontal plane of force, 3 feet in diameter and 1 inch thick, that floats 3 feet above the ground in an unoccupied space of your choice that you can see within range. The disk remains for the duration, and can hold up to 500 pounds. If more weight is placed on it, the spell ends, and everything on the disk falls to the ground.
The disk is immobile while you are within 20 feet of it. If you move more than 20 feet away from it, the disk follows you so that it remains within 20 feet of you. It can move across uneven terrain, up or down stairs, slopes and the like, but it can’t cross an elevation change of 10 feet or more. For example, the disk can’t move across a 10-foot-deep pit, nor could it leave such a pit if it was created at the bottom.
If you move more than 100 feet from the disk (typically because it can’t move around an obstacle to follow you), the spell ends.

Levitate:

One creature or loose object of your choice that you can see within range rises vertically, up to 20 feet, and remains suspended there for the duration. The spell can levitate a target that weighs up to 500 pounds. An unwilling creature that succeeds on a Constitution saving throw is unaffected.
The target can move only by pushing or pulling against a fixed object or surface within reach (such as a wall or a ceiling), which allows it to move as if it were climbing. You can change the target’s altitude by up to 20 feet in either direction on your turn. If you are the target, you can move up or down as part of your move. Otherwise, you can use your action to move the target, which must remain within the spell’s range.
When the spell ends, the target floats gently to the ground if it is still aloft.

To be clear I am not asking about whether I can move the disk over a hole, I am aware of that limitation and can easily put a plank over the hole and move the disk over the void, I am only asking about the vertical movement speed of the disk.

Can second internal hard disk cause infection after reinstall?

Lets say I have two internal hard disks, one for the operating system the other for backups. If i make sure to delete the MBR and partition table with dd if=/dev/zero of=/dev/sda bs=512 count=2048 of the disk with the operating system to avoid the possibility of a boot sector virus.

If I reinstall in what ways can that second hard disk be used to cause an infection of the primary disk with the operating system?

I was reading thata boot sector viruses can even spread to other hard drives you have installed or physical media you have plugged into your system.

So what impact can a boot sector virus on a backup drive have on on the primary drive? And any other threats I may have missed? I guess it could effect USB sticks plugged in?

how to set up multiple computers full disk encryption?

I want to set up my company’s laptops in a way that all files created on these laptops can only read by these laptops. If it is copy to a usb then that file is only readable when plug that USB in a company laptop. If plug in or copy to another non-authorized laptop then it is not readable.

Earn and Young is using this technique to protect their data but I don’t know what is it called and how to set it up. Please help 🙂 thanks guy

Access SATA disk disabled in BIOS

If a remote hacker or a malware gains full root/admin rights on a system, is there any way to access another SATA disk that has been hardware connected but disabled in BIOS ?

I am not sure if the disabled disk even has power in that case (I guess it has not) but I found the following post which raised some doubts : https://superuser.com/a/111009

OS considered : Windows or Linux

Threat Model : Physical access and BIOS reflash are out of scope as it is game over anyway in such cases.

Except this, consider full control of compromised disk system: hacker can issue any command, can modify MBR, kernel, flash the compromised disk firmware, …

MS SQL running out of Disk Space – can FileGroups be used to free up some space?


Problem

We have a Sql Server 2014 with a 1TB attached disk (on Azure) that’s running out of disk space. We have about 20GB’s left (maybe a few weeks of space). As such, we need to move some data off the CURRENT disk and onto a NEW disk.

Details

Server:

Microsoft SQL Server 2014 - 12.0.2548.0 (X64)      Jun  8 2015 11:08:03      Copyright (c) Microsoft Corporation     Web Edition (64-bit) on Windows NT 6.3 <X64> (Build 9600: ) (Hypervisor) 

MS-SQL 2014 is installed onto a classic Azure VM. This VM is in a classic VNET. The storage DISKS are also classic. As such, we couldn’t just expand the existing disk. MS-Support said that we need to update all of these, if we wish to leverage the modern Azure Storage to allow disk resizing, using the newer SSD disk, etc. TL;DR; we can’t take this offline for hours including all the other subsystems that communicate with the VM via IP address. Now, don’t turn this into a flame-fest .. this is what we’ve been given to work with and will need to fix all of this up later.

So right now, an idea what to try and leverage FILEGROUPS and to move one or more tables into a FILEGROUP and push this FILEGROUP onto another DISK which we have attached.

So the questions here are:

  • Is this a really really crazy and lame idea, first of all?
  • If it’s crap but OK, then will using FILEGROUPS actually move the data from the CURRENT disk onto the NEW disk (which frees up some disk space on the nearly full CURRENT DISK)?
  • If this is still possible, does moving these tables mean the data is locked/unavailable … which means were still back to our initial problem 🙁
  • What about logs? Moving this data means the logs just get a copy of this? (we are doing hourly and weekly backups, I believe).

It’s ok if the data is small, but here’s a quick look at some of our tables…

enter image description here

That first table is massive (with respect to the rest of the data). 750GB ish.

I was thinking of moving maybe the 2nd, 3rd of 4th line, in the result image. Remember how I said the infrastructure is all on OLD classic stuff? This means the HD’s are old and slow so copying data could take some time also.

As an example, I just tried to copy the .mdf‘s (this DB has 1 main mdf and 2 other small ones) from OLD over to NEW disks. that had a quick ETA of 24 hours.

Having the site offline for a few hours is totally acceptable. We can take stuff offline when our customers are asleep. but … 24 hours .. that hurts. The 24 hour idea was a simple test for:

  • Create new 2TB Disk (if possible)
  • turn off sql server.
  • copy mdf + log files to new disk. (24 hours or so)
  • point filegroups from old location to new location
  • start sql server again.

Now, we’re open to ideas and I know that stack exchange is not a site for ‘opinions’ so I’m trying to keep this on target with a suggested answer and to get feedback on it … but we’re open to other solutions to reduce the offline time.

So – can anyone help please?

In what ways can the contents of RAM be (inadvertently) written to disk?

I’m working on improving the security of my own system by mitigating the chance sensitive information, (e.g. encryption keys) stored in RAM, are inadvertently written to disk. As of now I know of three common ways this can occur and how they could be mitigated:

  1. The contents of RAM are copied to hiberfil.sys when Windows Hibernates
    • Solution: Disable Windows Hibernation
  2. Some contents of RAM are copied into the swap file.
    • Solution: Encrypt the swap file.
  3. Memory Dumps during Windows Blue-screens.
    • Solution: Disable memory dump file generation

Excluding these (as well as tools specifically designed to dump memory) are there any other reasons RAM could unintentionally be written to disk by the operating system?

I would really appreciate any help I could get!

Disk encryption with automatic reboot and no-network

I am using crytsetup with LUKS to encrypt a data drive, separate to the system drive, under Ubuntu 16.04. The issue I am facing is that this system will also be required to automatically start itself up in the event of power loss. The other constraint is that this system can not be connected to a network.

Essentially the only security risk with respect to the data is the case that someone physically steals the system with the HD on board. So of course I can provide an associated key to the drive but given that I have no network access, and yet I still require unattended rebooting, I’m a bit lost on how to proceed.

Looking for general thoughts on how to handle such a situation. Perhaps there are physical security solutions (i.e. self destructing USB -though who knows upon what condition given my requirements!) that might be helpful. Or really any comments from anyone who has faced the same constraint: i.e. encrypted drive with unattended reboot, and no network. Maybe I’m thinking about the problem the wrong way?

Thank you in advance.

How to manage disk space allocation for materialized views?

Summary: I have materialized views in oracle 11g that seem to hog disk space, unlike normal tables that mark rows as deleted and stats eventually show them as free space (allocated to the table, allowing reuse). Tablespace usage only grows for materialized views unlike stats for origin tables. Tested in Oracle 12c with same results. How to ensure MV reuse space from deleted rows?

What have I done? I have these partitioned materialized views set up in a separate schema, separate tablespace from the origin tables (i know they could have partitions created dynamically, call it technical debt).

CREATE MATERIALIZED VIEW replication_schema.origin_table PARTITION BY RANGE(tbl_timestamp)  (     PARTITION tbl_before_2016 VALUES LESS THAN (TO_TIMESTAMP('2016-01-01 00:00:00','YYYY-MM-DD HH24:MI:SS')),     PARTITION tbl_2016_01 VALUES LESS THAN (TO_TIMESTAMP('2016-02-01 00:00:00','YYYY-MM-DD HH24:MI:SS')),     PARTITION tbl_2016_02 VALUES LESS THAN (TO_TIMESTAMP('2016-03-01 00:00:00','YYYY-MM-DD HH24:MI:SS')), ...  PARTITION tbl_after_2025 VALUES LESS THAN (MAXVALUE) ) REFRESH FORCE ON DEMAND START WITH SYSDATE NEXT sysdate+1/1440 AS SELECT * FROM origin_schema.table; 

And they have some indexes on them as well, some global and some are local.

CREATE INDEX tbl_account_index ON replication_schema.origin_table (tbl_account DESC) LOCAL; CREATE INDEX tbl_column1_index ON replication_schema.origin_table (tbl_column1 DESC) LOCAL; CREATE INDEX tbl_column2_index ON replication_schema.origin_table (tbl_column2 DESC) LOCAL; CREATE INDEX tbl_column3_index ON replication_schema.origin_table (tbl_column3 DESC); CREATE INDEX tbl_column4_index ON replication_schema.origin_table (tbl_column4 DESC); 

Most of the time they get new rows (about 4M/mo) but users have set up a process to delete old rows from the origin table every two weeks. They can delete up to 500K/1M rows from each replicated table, every time.

There are seven materialized views in this schema. Each one extract data from one origin table.

What we see is that, contrary to what happens with the origin table, the space reported as free in dba_ tables does not change over time and tablespace usage only grows from these materialized views.

If I wait a while after deleting rows and run this query:

select df.tablespace_name "Tablespace", totalusedspace "Used MB", (df.totalspace - tu.totalusedspace) "Free MB", df.totalspace "Total MB", round(100 * ( (df.totalspace - tu.totalusedspace)/ df.totalspace)) "Pct. Free" from (select tablespace_name, round(sum(bytes) / 1048576) TotalSpace from dba_data_files  group by tablespace_name) df, (select round(sum(bytes)/(1024*1024)) totalusedspace, tablespace_name from dba_segments  group by tablespace_name) tu where df.tablespace_name = tu.tablespace_name and df.totalspace <>0 ; 

It shows an increase in the Free MB column (space in dba_data_files minus allocation declared in dba_segment) for origin tablespace but the used MB for replication never decrease, only increase on new rows (over three years now)

Tablespace      Used MB    Free MB  Total MB   Pct. Free SYSTEM          491        9        500        2 SYSAUX          1628       162      1790       9 UNDOTBS1        0          9645     9645       100 ORIGIN_DATA     2705       1391     4096       34 ORIGIN_REP_DATA **1975**   2121     4096       52 

That tablespace only holds these materialized views. There’s no other object there being used.

I tried the advisor to see what can I do:

variable id number; begin   declare   name varchar2(100);   descr varchar2(500);   obj_id number;   begin   name:='REPCHECK';   descr:='Replication advisory';    dbms_advisor.create_task (     advisor_name     => 'Segment Advisor',     task_id          => :id,     task_name        => name,     task_desc        => descr);    dbms_advisor.create_object (     task_name        => name,     object_type      => 'TABLE',     attr1            => 'REPLICATION_SCHEMA',     attr2            => 'ORIGIN_TABLE',     attr3            => NULL,     attr4            => NULL,     attr5            => NULL,     object_id        => obj_id);    dbms_advisor.set_task_parameter(     task_name        => name,     parameter        => 'recommend_all',     value            => 'TRUE');    dbms_advisor.execute_task(name);   end; end;  / 

And it says

Perform re-org on the origin_table object, estimated savings is xxx bytes

If I try querying recommendations through procedure:

select    tablespace_name,    allocated_space,    used_space reclaimable_space from    table(dbms_space.asa_recommendations('TRUE', 'TRUE', 'ALL')) 

It returns

ORIGIN_REP_DATA 100663296   38419844 

But I only get errors when trying to run SHRINK SPACE or COMPRESS options

ORA-10635: Invalid segment or tablespace type 10635. 00000 – “Invalid segment or tablespace type” *Cause: Cannot shrink the segment because it is not in auto segment space managed tablespace or it is not a data, index or lob segment. *Action: Check the tablespace and segment type and reissue the statement

Long story short: What can I do to avoiding disk space wasting in this materialized views? How to perform maintenance on them? Shall I drop them and recreate them? Datafiles usage in tablespace is growing about 10GB per month and I’m running out of time (and space). Thanks.