diff --git a/services/backup/src/constants.rs b/services/backup/src/constants.rs
index bb7778faf..55904dfb2 100644
--- a/services/backup/src/constants.rs
+++ b/services/backup/src/constants.rs
@@ -1,36 +1,41 @@
 // Assorted constants
 
 pub const AWS_REGION: &str = "us-east-2";
 pub const MPSC_CHANNEL_BUFFER_CAPACITY: usize = 1;
 pub const ID_SEPARATOR: &str = ":";
 
+// 400KiB limit (in docs there is KB but they mean KiB) -
+// https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ServiceQuotas.html
+// This includes both attribute names' and values' lengths
+pub const LOG_DATA_SIZE_DATABASE_LIMIT: usize = 1024 * 400;
+
 // Configuration defaults
 
 pub const DEFAULT_GRPC_SERVER_PORT: u64 = 50051;
 pub const DEFAULT_LOCALSTACK_URL: &str = "http://localhost:4566";
 pub const DEFAULT_BLOB_SERVICE_URL: &str = "http://localhost:50053";
 
 // Environment variable names
 
 pub const SANDBOX_ENV_VAR: &str = "COMM_SERVICES_SANDBOX";
 pub const LOG_LEVEL_ENV_VAR: &str =
   tracing_subscriber::filter::EnvFilter::DEFAULT_ENV;
 
 // DynamoDB constants
 
 pub const BACKUP_TABLE_NAME: &str = "backup-service-backup";
 pub const BACKUP_TABLE_FIELD_USER_ID: &str = "userID";
 pub const BACKUP_TABLE_FIELD_BACKUP_ID: &str = "backupID";
 pub const BACKUP_TABLE_FIELD_CREATED: &str = "created";
 pub const BACKUP_TABLE_FIELD_RECOVERY_DATA: &str = "recoveryData";
 pub const BACKUP_TABLE_FIELD_COMPACTION_HOLDER: &str = "compactionHolder";
 pub const BACKUP_TABLE_FIELD_ATTACHMENT_HOLDERS: &str = "attachmentHolders";
 pub const BACKUP_TABLE_INDEX_USERID_CREATED: &str = "userID-created-index";
 
 pub const LOG_TABLE_NAME: &str = "backup-service-log";
 pub const LOG_TABLE_FIELD_BACKUP_ID: &str = "backupID";
 pub const LOG_TABLE_FIELD_LOG_ID: &str = "logID";
 pub const LOG_TABLE_FIELD_PERSISTED_IN_BLOB: &str = "persistedInBlob";
 pub const LOG_TABLE_FIELD_VALUE: &str = "value";
 pub const LOG_TABLE_FIELD_ATTACHMENT_HOLDERS: &str = "attachmentHolders";
 pub const LOG_TABLE_FIELD_DATA_HASH: &str = "dataHash";
diff --git a/services/backup/src/database.rs b/services/backup/src/database.rs
index 1ed54d500..c0bf7f7c4 100644
--- a/services/backup/src/database.rs
+++ b/services/backup/src/database.rs
@@ -1,525 +1,573 @@
 use aws_sdk_dynamodb::{
   model::AttributeValue, output::GetItemOutput, Error as DynamoDBError,
 };
 use chrono::{DateTime, Utc};
 use std::{
   collections::HashMap,
   fmt::{Display, Formatter},
   sync::Arc,
 };
 use tracing::error;
 
 use crate::constants::{
   BACKUP_TABLE_FIELD_ATTACHMENT_HOLDERS, BACKUP_TABLE_FIELD_BACKUP_ID,
   BACKUP_TABLE_FIELD_COMPACTION_HOLDER, BACKUP_TABLE_FIELD_CREATED,
   BACKUP_TABLE_FIELD_RECOVERY_DATA, BACKUP_TABLE_FIELD_USER_ID,
   BACKUP_TABLE_INDEX_USERID_CREATED, BACKUP_TABLE_NAME,
   LOG_TABLE_FIELD_ATTACHMENT_HOLDERS, LOG_TABLE_FIELD_BACKUP_ID,
   LOG_TABLE_FIELD_DATA_HASH, LOG_TABLE_FIELD_LOG_ID,
   LOG_TABLE_FIELD_PERSISTED_IN_BLOB, LOG_TABLE_FIELD_VALUE, LOG_TABLE_NAME,
 };
 
 #[derive(Clone, Debug)]
 pub struct BackupItem {
   pub user_id: String,
   pub backup_id: String,
   pub created: DateTime<Utc>,
   pub recovery_data: String,
   pub compaction_holder: String,
   pub attachment_holders: String,
 }
 
 impl BackupItem {
   pub fn new(
     user_id: String,
     backup_id: String,
     compaction_holder: String,
   ) -> Self {
     BackupItem {
       user_id,
       backup_id,
       compaction_holder,
       created: chrono::Utc::now(),
       // TODO: Recovery data is mocked with random string
       recovery_data: crate::utils::generate_random_string(
         20,
         &mut rand::thread_rng(),
       ),
       attachment_holders: String::new(),
     }
   }
 }
 
+static LOG_ITEM_HEADERS_SIZE: usize = {
+  let mut size: usize = 0;
+  size += LOG_TABLE_FIELD_BACKUP_ID.as_bytes().len();
+  size += LOG_TABLE_FIELD_LOG_ID.as_bytes().len();
+  size += LOG_TABLE_FIELD_PERSISTED_IN_BLOB.as_bytes().len();
+  size += LOG_TABLE_FIELD_VALUE.as_bytes().len();
+  size += LOG_TABLE_FIELD_ATTACHMENT_HOLDERS.as_bytes().len();
+  size += LOG_TABLE_FIELD_DATA_HASH.as_bytes().len();
+  size
+};
+
 #[derive(Clone, Debug)]
 pub struct LogItem {
   pub backup_id: String,
   pub log_id: String,
   pub persisted_in_blob: bool,
   pub value: String,
   pub attachment_holders: String,
   pub data_hash: String,
 }
 
+impl LogItem {
+  /// Calculates size based on raw log item components,
+  /// without allocating a new item
+  pub fn size_from_components(
+    backup_id: &str,
+    log_id: &str,
+    log_hash: &str,
+    data: &[u8],
+  ) -> usize {
+    let mut size: usize = LOG_ITEM_HEADERS_SIZE;
+    size += backup_id.as_bytes().len();
+    size += log_id.as_bytes().len();
+    size += data.len();
+    size += log_hash.as_bytes().len();
+
+    // persistent in blob, attachment holders, use defaults here
+    size += false.to_string().as_bytes().len();
+    size += "".as_bytes().len();
+
+    size
+  }
+
+  /// Total size of this item in the DynamoDB table. This value must be
+  /// smaller than [`crate::constants::LOG_DATA_SIZE_DATABASE_LIMIT`]
+  /// in order to successfully put this item into a DynamoDB database.
+  pub fn total_size(&self) -> usize {
+    let mut size: usize = LOG_ITEM_HEADERS_SIZE;
+    size += self.backup_id.as_bytes().len();
+    size += self.log_id.as_bytes().len();
+    size += self.persisted_in_blob.to_string().as_bytes().len();
+    size += self.value.as_bytes().len();
+    size += self.attachment_holders.as_bytes().len();
+    size += self.data_hash.as_bytes().len();
+    size
+  }
+}
+
 #[derive(Clone)]
 pub struct DatabaseClient {
   client: Arc<aws_sdk_dynamodb::Client>,
 }
 
 impl DatabaseClient {
   pub fn new(aws_config: &aws_types::SdkConfig) -> Self {
     DatabaseClient {
       client: Arc::new(aws_sdk_dynamodb::Client::new(aws_config)),
     }
   }
 
   // backup item
   pub async fn put_backup_item(
     &self,
     backup_item: BackupItem,
   ) -> Result<(), Error> {
     let item = HashMap::from([
       (
         BACKUP_TABLE_FIELD_USER_ID.to_string(),
         AttributeValue::S(backup_item.user_id),
       ),
       (
         BACKUP_TABLE_FIELD_CREATED.to_string(),
         AttributeValue::S(backup_item.created.to_rfc3339()),
       ),
       (
         BACKUP_TABLE_FIELD_BACKUP_ID.to_string(),
         AttributeValue::S(backup_item.backup_id),
       ),
       (
         BACKUP_TABLE_FIELD_RECOVERY_DATA.to_string(),
         AttributeValue::S(backup_item.recovery_data),
       ),
       (
         BACKUP_TABLE_FIELD_COMPACTION_HOLDER.to_string(),
         AttributeValue::S(backup_item.compaction_holder),
       ),
       (
         BACKUP_TABLE_FIELD_ATTACHMENT_HOLDERS.to_string(),
         AttributeValue::S(backup_item.attachment_holders),
       ),
     ]);
 
     self
       .client
       .put_item()
       .table_name(BACKUP_TABLE_NAME)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to put backup item");
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 
   pub async fn find_backup_item(
     &self,
     user_id: &str,
     backup_id: &str,
   ) -> Result<Option<BackupItem>, Error> {
     let item_key = HashMap::from([
       (
         BACKUP_TABLE_FIELD_USER_ID.to_string(),
         AttributeValue::S(user_id.to_string()),
       ),
       (
         BACKUP_TABLE_FIELD_BACKUP_ID.to_string(),
         AttributeValue::S(backup_id.to_string()),
       ),
     ]);
 
     match self
       .client
       .get_item()
       .table_name(BACKUP_TABLE_NAME)
       .set_key(Some(item_key))
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to find backup item");
         Error::AwsSdk(e.into())
       })? {
       GetItemOutput {
         item: Some(item), ..
       } => {
         let backup_item = parse_backup_item(item)?;
         Ok(Some(backup_item))
       }
       _ => Ok(None),
     }
   }
 
   pub async fn find_last_backup_item(
     &self,
     user_id: &str,
   ) -> Result<Option<BackupItem>, Error> {
     let response = self
       .client
       .query()
       .table_name(BACKUP_TABLE_NAME)
       .index_name(BACKUP_TABLE_INDEX_USERID_CREATED)
       .key_condition_expression("#userID = :valueToMatch")
       .expression_attribute_names("#userID", BACKUP_TABLE_FIELD_USER_ID)
       .expression_attribute_values(
         ":valueToMatch",
         AttributeValue::S(user_id.to_string()),
       )
       .limit(1)
       .scan_index_forward(false)
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to find last backup");
         Error::AwsSdk(e.into())
       })?;
 
     match response.items.unwrap_or_default().pop() {
       Some(item) => {
         let backup_item = parse_backup_item(item)?;
         Ok(Some(backup_item))
       }
       None => Ok(None),
     }
   }
 
   pub async fn remove_backup_item(&self, backup_id: &str) -> Result<(), Error> {
     self
       .client
       .delete_item()
       .table_name(BACKUP_TABLE_NAME)
       .key(
         BACKUP_TABLE_FIELD_BACKUP_ID,
         AttributeValue::S(backup_id.to_string()),
       )
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to remove backup item");
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 
   // log item
   pub async fn put_log_item(&self, log_item: LogItem) -> Result<(), Error> {
     let item = HashMap::from([
       (
         LOG_TABLE_FIELD_BACKUP_ID.to_string(),
         AttributeValue::S(log_item.backup_id),
       ),
       (
         LOG_TABLE_FIELD_LOG_ID.to_string(),
         AttributeValue::S(log_item.log_id),
       ),
       (
         LOG_TABLE_FIELD_PERSISTED_IN_BLOB.to_string(),
         AttributeValue::Bool(log_item.persisted_in_blob),
       ),
       (
         LOG_TABLE_FIELD_VALUE.to_string(),
         AttributeValue::S(log_item.value),
       ),
       (
         LOG_TABLE_FIELD_DATA_HASH.to_string(),
         AttributeValue::S(log_item.data_hash),
       ),
       (
         LOG_TABLE_FIELD_ATTACHMENT_HOLDERS.to_string(),
         AttributeValue::S(log_item.attachment_holders),
       ),
     ]);
 
     self
       .client
       .put_item()
       .table_name(LOG_TABLE_NAME)
       .set_item(Some(item))
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to put log item");
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 
   pub async fn find_log_item(
     &self,
     backup_id: &str,
     log_id: &str,
   ) -> Result<Option<LogItem>, Error> {
     let item_key = HashMap::from([
       (
         LOG_TABLE_FIELD_BACKUP_ID.to_string(),
         AttributeValue::S(backup_id.to_string()),
       ),
       (
         LOG_TABLE_FIELD_LOG_ID.to_string(),
         AttributeValue::S(log_id.to_string()),
       ),
     ]);
 
     match self
       .client
       .get_item()
       .table_name(LOG_TABLE_NAME)
       .set_key(Some(item_key))
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to find log item");
         Error::AwsSdk(e.into())
       })? {
       GetItemOutput {
         item: Some(item), ..
       } => {
         let log_item = parse_log_item(item)?;
         Ok(Some(log_item))
       }
       _ => Ok(None),
     }
   }
 
   pub async fn find_log_items_for_backup(
     &self,
     backup_id: &str,
   ) -> Result<Vec<LogItem>, Error> {
     let response = self
       .client
       .query()
       .table_name(LOG_TABLE_NAME)
       .key_condition_expression("#backupID = :valueToMatch")
       .expression_attribute_names("#backupID", LOG_TABLE_FIELD_BACKUP_ID)
       .expression_attribute_values(
         ":valueToMatch",
         AttributeValue::S(backup_id.to_string()),
       )
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to find log items for backup");
         Error::AwsSdk(e.into())
       })?;
 
     if response.count == 0 {
       return Ok(Vec::new());
     }
 
     let mut results: Vec<LogItem> =
       Vec::with_capacity(response.count() as usize);
     for item in response.items.unwrap_or_default() {
       let log_item = parse_log_item(item)?;
       results.push(log_item);
     }
     Ok(results)
   }
 
   pub async fn remove_log_item(&self, log_id: &str) -> Result<(), Error> {
     self
       .client
       .delete_item()
       .table_name(LOG_TABLE_NAME)
       .key(
         LOG_TABLE_FIELD_LOG_ID,
         AttributeValue::S(log_id.to_string()),
       )
       .send()
       .await
       .map_err(|e| {
         error!("DynamoDB client failed to remove log item");
         Error::AwsSdk(e.into())
       })?;
 
     Ok(())
   }
 }
 
 #[derive(
   Debug, derive_more::Display, derive_more::From, derive_more::Error,
 )]
 pub enum Error {
   #[display(...)]
   AwsSdk(DynamoDBError),
   #[display(...)]
   Attribute(DBItemError),
 }
 
 #[derive(Debug, derive_more::Error, derive_more::Constructor)]
 pub struct DBItemError {
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
   attribute_error: DBItemAttributeError,
 }
 
 impl Display for DBItemError {
   fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
     match &self.attribute_error {
       DBItemAttributeError::Missing => {
         write!(f, "Attribute {} is missing", self.attribute_name)
       }
       DBItemAttributeError::IncorrectType => write!(
         f,
         "Value for attribute {} has incorrect type: {:?}",
         self.attribute_name, self.attribute_value
       ),
       error => write!(
         f,
         "Error regarding attribute {} with value {:?}: {}",
         self.attribute_name, self.attribute_value, error
       ),
     }
   }
 }
 
 #[derive(Debug, derive_more::Display, derive_more::Error)]
 pub enum DBItemAttributeError {
   #[display(...)]
   Missing,
   #[display(...)]
   IncorrectType,
   #[display(...)]
   InvalidTimestamp(chrono::ParseError),
 }
 
 fn parse_string_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<String, DBItemError> {
   match attribute_value {
     Some(AttributeValue::S(value)) => Ok(value),
     Some(_) => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_bool_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<bool, DBItemError> {
   match attribute_value {
     Some(AttributeValue::Bool(value)) => Ok(value),
     Some(_) => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::IncorrectType,
     )),
     None => Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     )),
   }
 }
 
 fn parse_datetime_attribute(
   attribute_name: &'static str,
   attribute_value: Option<AttributeValue>,
 ) -> Result<DateTime<Utc>, DBItemError> {
   if let Some(AttributeValue::S(datetime)) = &attribute_value {
     // parse() accepts a relaxed RFC3339 string
     datetime.parse().map_err(|e| {
       DBItemError::new(
         attribute_name,
         attribute_value,
         DBItemAttributeError::InvalidTimestamp(e),
       )
     })
   } else {
     Err(DBItemError::new(
       attribute_name,
       attribute_value,
       DBItemAttributeError::Missing,
     ))
   }
 }
 
 fn parse_backup_item(
   mut item: HashMap<String, AttributeValue>,
 ) -> Result<BackupItem, DBItemError> {
   let user_id = parse_string_attribute(
     BACKUP_TABLE_FIELD_USER_ID,
     item.remove(BACKUP_TABLE_FIELD_USER_ID),
   )?;
   let backup_id = parse_string_attribute(
     BACKUP_TABLE_FIELD_BACKUP_ID,
     item.remove(BACKUP_TABLE_FIELD_BACKUP_ID),
   )?;
   let created = parse_datetime_attribute(
     BACKUP_TABLE_FIELD_CREATED,
     item.remove(BACKUP_TABLE_FIELD_CREATED),
   )?;
   let recovery_data = parse_string_attribute(
     BACKUP_TABLE_FIELD_RECOVERY_DATA,
     item.remove(BACKUP_TABLE_FIELD_RECOVERY_DATA),
   )?;
   let compaction_holder = parse_string_attribute(
     BACKUP_TABLE_FIELD_COMPACTION_HOLDER,
     item.remove(BACKUP_TABLE_FIELD_COMPACTION_HOLDER),
   )?;
   let attachment_holders = parse_string_attribute(
     BACKUP_TABLE_FIELD_ATTACHMENT_HOLDERS,
     item.remove(BACKUP_TABLE_FIELD_ATTACHMENT_HOLDERS),
   )?;
   Ok(BackupItem {
     user_id,
     backup_id,
     created,
     recovery_data,
     compaction_holder,
     attachment_holders,
   })
 }
 
 fn parse_log_item(
   mut item: HashMap<String, AttributeValue>,
 ) -> Result<LogItem, DBItemError> {
   let backup_id = parse_string_attribute(
     LOG_TABLE_FIELD_BACKUP_ID,
     item.remove(LOG_TABLE_FIELD_BACKUP_ID),
   )?;
   let log_id = parse_string_attribute(
     LOG_TABLE_FIELD_LOG_ID,
     item.remove(LOG_TABLE_FIELD_LOG_ID),
   )?;
   let persisted_in_blob = parse_bool_attribute(
     LOG_TABLE_FIELD_PERSISTED_IN_BLOB,
     item.remove(LOG_TABLE_FIELD_PERSISTED_IN_BLOB),
   )?;
   let value = parse_string_attribute(
     LOG_TABLE_FIELD_VALUE,
     item.remove(LOG_TABLE_FIELD_VALUE),
   )?;
   let data_hash = parse_string_attribute(
     LOG_TABLE_FIELD_DATA_HASH,
     item.remove(LOG_TABLE_FIELD_DATA_HASH),
   )?;
   let attachment_holders = parse_string_attribute(
     LOG_TABLE_FIELD_ATTACHMENT_HOLDERS,
     item.remove(LOG_TABLE_FIELD_ATTACHMENT_HOLDERS),
   )?;
   Ok(LogItem {
     log_id,
     backup_id,
     persisted_in_blob,
     value,
     data_hash,
     attachment_holders,
   })
 }